Allen G Harmsen

Montana State University, Bozeman, Montana, United States

Are you Allen G Harmsen?

Claim your profile

Publications (92)

  • Source
    [Show abstract] [Hide abstract] ABSTRACT: Understanding how cultural values influence undergraduate students’ science research experiences and career interest is important in efforts to broaden participation and to diversify the biomedical research workforce. The results from our prospective longitudinal study demonstrated that underrepresented minority student (URM) research assistants who see the altruistic value of conducting biomedical research feel more psychologically involved with their research over time, which, in turn, enhances their interest in pursuing a scientific research career. These altruistic motives are uniquely influential to URM students and appear to play an important role in influencing their interest in scientific research careers. Furthermore, seeing how research can potentially affect society and help one's community does not replace typical motives for scientific discovery (e.g., passion, curiosity, achievement), which are important for all students. These findings point to simple strategies for educators, training directors, and faculty mentors to improve retention among undergraduate URM students in biomedicine and the related sciences.
    Full-text Article · Dec 2014 · BioScience
  • Agnieszka Rynda‐Apple · Ann Harmsen · Anfin S. Erickson · [...] · Allen G. Harmsen
    [Show abstract] [Hide abstract] ABSTRACT: Superinfection in mice at day 7 post-influenza infection exacerbates bacterial pneumonia at least in part via downstream effects of increased IFN-γ signaling. Here we show that up to 3 days post-influenza infection, mice have reduced susceptibility to superinfection with methicillin-resistant Staphylococcus aureus (MRSA), but that superinfection during that time exacerbated influenza disease. This was due to IL-13 signaling that was advantageous for resolving MRSA infection via inhibition of IFN-γ, but was detrimental to the clearance of influenza virus. However, if superinfection did not occur until the near resolution of influenza infection (day 7), IL-13 signaling was inhibited, at least in part by upregulation of IL-13 decoy receptor (IL-13Rα2), which in turn caused increases in IFN-γ signaling and exacerbation of bacterial infection. Understanding these cytokine sequelae is critical to development of immunotherapies for influenza-MRSA coinfection since perturbations of these sequelae at the wrong time could increase susceptibility to MRSA and/or influenza.This article is protected by copyright. All rights reserved
    Article · Nov 2014 · European Journal of Immunology
  • Source
    Laura E Richert · Agnieszka Rynda-Apple · Ann L Harmsen · [...] · Allen G Harmsen
    [Show abstract] [Hide abstract] ABSTRACT: Recent evidence suggests that an individual's unique history and sequence of exposures to pathogens and antigens may dictate downstream immune responses to disparate antigens. We show that the intranasal delivery of non-replicative virus-like particles (VLPs), which bear structural but no antigenic similarities to respiratory pathogens, acts to prime the lungs of both C56BL/6 and BALB/c mice, facilitating heightened and accelerated primary immune responses to high-dose influenza challenge, thus providing a non-pathogenic model of innate imprinting. These responses correspond closely to those observed following natural infection with the opportunistic fungus, Pneumocystis murina, and are characterized by accelerated antigen processing by dendritic cells (DCs) and alveolar macrophages (AMs), an enhanced influx of cells to the local tracheobronchial lymph node (TBLN), and early upregulation of T-cell co-stimulatory/adhesion molecules. CD11c(+) cells which have been directly exposed to VLPs or Pneumocystis are necessary in facilitating enhanced clearance of influenza virus, and the repopulation of the lung by Ly-6C(+) precursors relies on CCR2 expression. Thus, immune imprinting 72 hours after VLP-, or 2 weeks after Pneumocystis-priming is CCR2-mediated and results from the enhanced antigen processing, maturation, and trafficking abilities of DCs and AMs, which cause accelerated influenza-specific primary immune responses and result in superior viral clearance. This article is protected by copyright. All rights reserved.
    Full-text Article · Feb 2014 · European Journal of Immunology
  • Source
    Laura E Richert · Ann L Harmsen · Agnieszka Rynda-Apple · [...] · Allen G Harmsen
    [Show abstract] [Hide abstract] ABSTRACT: Background: Exposure of the lungs to an antigen or pathogen elicits the formation of lymphoid satellite islands termed inducible bronchus-associated lymphoid tissue (iBALT). However, little is known about how the presence of iBALT, induced by a stimulus unrelated to the subsequent challenge agent, influences systemic immunity in distal locations, whether it be independently, antagonistically, or synergistically. Here, we determined the kinetics of the influenza-specific responses in the iBALT, tracheobronchial lymph node (TBLN), and spleen of mice with and without pre-formed iBALT. Methods and results: Mice with VLP-induced iBALT or no pre-formed iBALT were challenged with influenza. We found that, as we have previously described, those mice whose lungs contained pre-formed iBALT were protected from morbidity, and furthermore, that these mice had increased dendritic cell, and alveolar macrophage accumulation in both the iBALT and TBLNs. This translated to similarly accelerated kinetics and intensified influenza-specific CD4(+), but not CD8(+) T cell responses in the iBALT, TBLN, and spleen. This expansion was then followed by a more rapid T cell contraction in all lymphoid tissues in the mice with pre-formed iBALT. Conclusions: Thus, iBALT itself may not be responsible for the accelerated primary immune response we observe in mice with pre-formed iBALT, but may contribute to an overall accelerated local and systemic primary CD4(+), but not CD8(+) T cell response. Furthermore, less damaging immune responses observed in mice with pre-formed iBALT may be due to a quicker contraction of CD4(+) T cell responses in both local and systemic secondary lymphoid tissue.
    Full-text Article · Dec 2013 · Lymphatic Research and Biology
  • Source
    [Show abstract] [Hide abstract] ABSTRACT: Here we present a biomimetic strategy for nanoparticle design for controlled immune response through encapsulation of conserved internal influenza proteins on the interior of virus like particles (VLPs) to direct CD8+ cytotoxic T cell protection. Programmed encapsulation and sequestration of the conserved nucleoprotein (NP) from influenza on the interior of the VLP derived from the bacteriophage P22 results in a vaccine that provides multi-strain protection against 100 times lethal doses of influenza in an NP specific CD8+ T cell-dependent manner. VLP assembly and encapsulation of the immunogenic NP cargo protein is the result of a genetically programmed self-assembly making this strategy amendable to the quick production of vaccines to rapidly emerging pathogens. Addition of adjuvants or targeting molecules were not required for eliciting the protective response.
    Full-text Article · Mar 2013 · ACS Nano
  • Matthew Calverley · Sara Erickson · Amanda J Read · Allen G Harmsen
    [Show abstract] [Hide abstract] ABSTRACT: Coxiella burnetii, the causative agent of Q fever, is a zoonotic disease with potentially life-threatening complications in humans. Inhalation of low doses of Coxiella bacteria can result in infection of the host alveolar macrophage (AM). However, it is not known whether a subset of AMs within the heterogeneous population of macrophages in the infected lung is particularly susceptible to infection. We have found that lower doses of both phase I and phase II Nine Mile C. burnetii multiply and are less readily cleared from the lungs of mice compared to higher infectious doses. We have additionally identified AM resident within the lung prior to and shortly following infection, opposed to newly recruited monocytes entering the lung during infection, as being most susceptible to infection. These resident cells remain infected up to twelve days after the onset of infection, serving as a permissive niche for the maintenance of bacterial infection. A subset of infected resident AMs undergo a distinguishing phenotypic change during the progression of infection exhibiting an increase in surface integrin CD11b expression and continued expression of the surface integrin CD11c. The low rate of phase I and II Nine Mile C. burnetii growth in murine lungs may be a direct result of the limited size of the susceptible resident AM cell population.
    Article · Dec 2012 · PLoS ONE
  • Dataset: Figure S1
    Matthew Calverley · Sara Erickson · Amanda J. Read · Allen G. Harmsen
    [Show abstract] [Hide abstract] ABSTRACT: Lower doses of NMII resulted in greater relative bacterial numbers in the lungs of BALB/c Mice. BALB/c mice were infected with either 103, 105 or 107 NMII Coxiella. Bacterial burdens in lung tissue were assessed 2 (A), 9 (B), 16 (C) or 24 (D) days PI by quantitative RT-PCR. Data is expressed as Log10 change in total genome copies per lung (Endpoint bacterial genome copies per lung/Inoculum). Groups were comprised of 4–5 mice with Mean and SEM plotted for each group. Relative to all other inoculum concentrations, the 103 group showed a significant increase in bacterial burden across the timecourse of infection. The 105 group showed a significant initial increase in bacterial burden and a subsequent significant reduction in overall clearance of bacteria, relative to high dose infections. The 107 group showed significant bacterial clearance relative to the other two doses from 9 days PI onward (ANOVA p<0.05). (TIFF)
    Dataset · Dec 2012
  • Dataset: Figure S3
    Matthew Calverley · Sara Erickson · Amanda J. Read · Allen G. Harmsen
    [Show abstract] [Hide abstract] ABSTRACT: Lower doses of NMI resulted in greater relative bacterial numbers in the lungs of BALB/c Mice. A) BALB/c mice were infected with either 103, 105 or 107 NMI Coxiella. Bacterial burdens in lung tissue were assessed 2 (A), 9 (B), 16 (C) and 23 (D) days PI by quantitative RT-PCR. Data is expressed as Log10 change in total genome copies per lung. Groups were comprised of 4–5 mice with Mean and SEM plotted for each group. Relative to the other inoculum concentrations, the 103 group showed a significant increase in bacterial burden from 9 days PI onward. The 105 group showed a significant increase in bacterial burden, relative to high dose infections from 9 days PI onward. The 107 group showed significant clearance relative to the other two doses from 16 days PI onward (ANOVA p<0.05). (TIFF)
    Dataset · Dec 2012
  • Dataset: Figure S4
    Matthew Calverley · Sara Erickson · Amanda J. Read · Allen G. Harmsen
    [Show abstract] [Hide abstract] ABSTRACT: Lower doses of NMI resulted in greater relative bacterial numbers in the spleen of BALB/c Mice. A) BALB/c mice were infected with either 103, 105 or 107 NMI Coxiella. Bacterial burdens in spleen tissue were assessed 2 (A), 9 (B), 16 (C) and 23 (D) days PI by quantitative RT-PCR. Data is expressed as Log10 change in total genome copies per spleen. Groups were comprised of 4–5 mice with Mean and SEM plotted for each group. Relative to the other inoculum concentrations, the 103 group showed a significant increase in bacterial burden at 9 days PI. The 107 group showed significant clearance relative to the other two doses from 9 days PI onward (ANOVA p<0.05). (TIFF)
    Dataset · Dec 2012
  • Dataset: Figure S2
    Matthew Calverley · Sara Erickson · Amanda J. Read · Allen G. Harmsen
    [Show abstract] [Hide abstract] ABSTRACT: High dose NMII infection did not result in increased clinical symptoms of systemic infection in BALB/c Mice. A) BALB/c mice were infected with either 103, 105 or 107 NMII Coxiella. Body weights were recorded daily from day 0 to day 24 PI. Groups were comprised of 4–5 mice with Mean and SEM plotted for each group. Although, there were small significant differences in final body weights among the three doses, none of the doses lost weight across the course of the infection. B) BALB/c mice were infected with either 103, 105 or 107 NMII Coxiella and spleen weights were taken at each endpoint (days 2, 9, 16 and 24 PI). Groups were comprised of 4–5 mice with Mean spleen weight as a percentage of body weight and SEM plotted for each group. There are no significant differences between groups or across the timecourse of infection. (TIFF)
    Dataset · Dec 2012
  • Agnieszka Rynda-Apple · Erin Dobrinen · Mark McAlpine · [...] · Allen G Harmsen
    [Show abstract] [Hide abstract] ABSTRACT: The importance of the priming of the lung environment by past infections is being increasingly recognized. Exposure to any given antigen can either improve or worsen the outcome of subsequent lung infections, depending on the immunological history of the host. Thus, an ability to impart transient alterations in the lung environment in anticipation of future insult could provide an important novel therapy for emerging infectious diseases. In this study, we show that nasal administration of virus-like particles (VLPs) before, or immediately after, lethal challenge with methicillin-resistant Staphylococcus aureus (MRSA) of mice i) ensures complete recovery from lung infection and near absolute clearance of bacteria within 12 hours of challenge, ii) reduces host response-induced lung tissue damage, iii) promotes recruitment and efficient bacterial clearance by neutrophils and CD11c(+) cells, and iv) protects macrophages from MRSA-induced necrosis. VLP-mediated protection against MRSA relied on innate immunity. Complete recovery occurred in VLP-dosed mice with severe combined immunodeficiency, but not in wild-type mice depleted of either Ly6G(+) or CD11c(+) cells. Early IL-13 production associated with VLP-induced CD11c(+) cells was essential for VLP-induced protection. These results indicate that VLP-induced alteration of the lung environment protects the host from lethal MRSA pneumonia by enhancing phagocyte recruitment and killing and by reducing inflammation-induced tissue damage via IL-13-dependent mechanisms.
    Article · May 2012 · American Journal Of Pathology
  • Source
    Laura E Richert · Amy E Servid · Ann L Harmsen · [...] · Allen G Harmsen
    [Show abstract] [Hide abstract] ABSTRACT: We show that a model antigen, ovalbumin (OVA), can be chemically conjugated to the exterior of a small heat shock protein (sHsp) cage that has structural similarities to virus-like particles (VLPs). OVA-sHsp conjugation efficiency was dependent upon the stoichiometry and the length of the small molecule linker utilized, and the attachment position on the sHsp cage. When conjugated OVA-sHsp was delivered intranasally to naïve mice, the resulting immune response to OVA was accelerated and intensified, and OVA-specific IgG1 responses were apparent within 5 days after a single immunizing dose, illustrating its utility for vaccine development. If animals were pretreated with a disparate VLP, P22 (a non-replicative bacteriophage capsid), before OVA-sHsp conjugate immunization, OVA-specific IgG1 responses were apparent already by 4 days after a single immunizing dose of conjugate in OVA-naïve mice. Additionally, the mice pretreated with P22 produced high titer mucosal IgA, and isotype-switched OVA-specific serum IgG. Similarly, sHsp pretreatment enhanced the accumulation of lung germinal center B cells, T follicular helper cells, and increased polymeric Ig receptor expression, priming the lungs for subsequent IgG and IgA responses to influenza virus challenge. Thus, sHsp nanoparticles elicited quick and intense antibody responses and these accelerated responses could similarly be induced to antigen chemically conjugated to the sHsp. Pretreatment of mice with P22 further accelerated the onset of the antibody response to OVA-sHsp, demonstrating the utility of conjugating antigens to VLPs for pre-, or possibly post-exposure prophylaxis of lung, all without the need for adjuvant.
    Full-text Article · Mar 2012 · Vaccine
  • Steve D Swain · Nicole N Meissner · Dan W Siemsen · [...] · Allen G Harmsen
    [Show abstract] [Hide abstract] ABSTRACT: It is widely held that exposure to pathogens such as fungi can be an agent of comorbidity, such as exacerbation of asthma or chronic obstructive pulmonary disease. Although many studies have examined allergic responses to fungi and their effects on pulmonary function, the possible pathologic implications of the early innate responses to fungal pathogens have not been explored. We examined early responses to the atypical fungus Pneumocystis in two common strains of mice in terms of overall immunological response and related pathology, such as cell damage and airway hyperresponsiveness (AHR). We found a strong strain-specific response in BALB/c mice that included recruitment of neutrophils, NK, NKT, and CD4 T cells. This response was accompanied by elevated indicators of lung damage (bronchoalveolar lavage fluid albumin and LDH) and profound AHR. This early response was absent in C57BL/6 mice, although both strains exhibited a later response associated with the clearance of Pneumocystis. We found that this AHR could not be attributed exclusively to the presence of recruited neutrophils, NKT, NK, or CD4 cells or to the actions of IFN-γ or IL-4. However, in the absence of STAT6 signaling, AHR and inflammatory cell recruitment were virtually absent. Gene expression analysis indicated that this early response included activation of several transcription factors that could be involved in pulmonary remodeling. These results show that exposure to a fungus such as Pneumocystis can elicit pulmonary responses that may contribute to morbidity, even without prior sensitization, in the context of certain genetic backgrounds.
    Article · Sep 2011 · American Journal of Respiratory Cell and Molecular Biology
  • Dataset: Figure S3
    [Show abstract] [Hide abstract] ABSTRACT: Multiparameter analysis of PI-WCV vaccination induced peptides specific CD4+ T cells. CD4+ T cells recognition of positive peptides identified by IFN-γ ELISPOT were tested in multicolor ICCS assay as described in material and methods. 10 ug of each peptide was used to stimulate 2×106 lymphocytes from four mice immunized with PI-WCV 10 days earlier in the context of IFA and CpG. Cells were gated on viable CD3+CD4+IFN-γ+ T cells. A representative experiment of four total experiments is shown. Percentages of TNF-α producing CD4+ T cells following stimulation with lysed Nine Mile phase I C. burnetii and peptides are shown. (TIF)
    Dataset · Mar 2011
  • Dataset: Figure S4
    [Show abstract] [Hide abstract] ABSTRACT: Peptide immunization does not protect from weight loss after challenge or bacterial burden. A) Change in body weights of C57BL/6 mice immunized with either PBS alone, OVA or epitope CBU 038369–83 in the context of CFA, or PI-WCV. After intratracheal infection with 103 genome copies of C. burnetii Nine Mile phase I, body weight change was expressed as a percentage of the initial body weight prior to infection and significant differences were identified at days 7 and 10 p.i. (p<0.01). No protective effect of the epitope immunization was observed in comparison to the immunization with PBS or the irrelevant OVA epitope. Data is representative of one of two independent experiments with 4–5 mice per group. B) 14 days post infection mice were euthanized and the bacterial burden in the lung was determined by PCR. No protective effect of the epitope immunization was observed in comparison to the immunization with PBS or the irrelevant OVA epitope. In contrast, immunization with heat killed PI-WCV (positive control) resulted in significantly lower bacterial burden (p<0.01). (TIF)
    Dataset · Mar 2011
  • Dataset: Figure S1
    [Show abstract] [Hide abstract] ABSTRACT: CD4+ T cells recognition of PI-WCV derived H-2 I-Ab epitopes in IL-2 ICCS assays. CD4+ T cells recognition of positive peptides identified by IFN-γ ELISPOT were tested in ICCS assay. 10 ug of each peptide was used to stimulate 2×106 lymphocytes from four mice immunized with PI-WCV 10 days earlier in the context of IFA and CpG. A representative experiment of four total experiments is shown. Percentages of IL-2 producing CD4+ T cells following stimulation with lysed Nine Mile phase I C. burnetii and peptides are shown. A peptide was considered positive if the average of the individual experiments resulted in at least >1 SD above background (0.009%, Medium +DMSO). (TIF)
    Dataset · Mar 2011
  • Dataset: Table S1
    [Show abstract] [Hide abstract] ABSTRACT: Complete peptide set and screening results. (DOC)
    Dataset · Mar 2011
  • Dataset: Figure S2
    [Show abstract] [Hide abstract] ABSTRACT: CD4+ T cells recognition of PI-WCV derived H-2 I-Ab epitopes in TNF-α ICCS assays. CD4+ T cells recognition of positive peptides identified by IFN-γ ELISPOT were tested in ICCS assay. 10 ug of each peptide was used to stimulate 2×106 lymphocytes from four mice immunized with PI-WCV 10 days earlier in the context of IFA and CpG. A representative experiment of four total experiments is shown. Percentages of TNF-α producing CD4+ T cells following stimulation with lysed Nine Mile Phase I C. burnetii and peptides are shown. A peptide was considered positive if the average of the individual experiments resulted in at least >1 SD above background (0.011%, Medium +DMSO). (TIF)
    Dataset · Mar 2011
  • Source
    [Show abstract] [Hide abstract] ABSTRACT: Coxiella burnetii is an obligate intracellular gram-negative bacterium that causes acute Q fever and chronic infections in humans. A killed, whole cell vaccine is efficacious, but vaccination can result in severe local or systemic adverse reactions. Although T cell responses are considered pivotal for vaccine derived protective immunity, the epitope targets of CD4(+) T cell responses in C. burnetii vaccination have not been elucidated. Since mapping CD4(+) epitopes in a genome with over 2,000 ORFs is resource intensive, we focused on 7 antigens that were known to be targeted by antibody responses. 117 candidate peptides were selected from these antigens based on bioinformatics predictions of binding to the murine MHC class II molecule H-2 IA(b). We screened these peptides for recognition by IFN-γ producing CD4(+) T cell in phase I C. burnetii whole cell vaccine (PI-WCV) vaccinated C57BL/6 mice and identified 8 distinct epitopes from four different proteins. The identified epitope targets account for 8% of the total vaccination induced IFN-γ producing CD4(+) T cells. Given that less than 0.4% of the antigens contained in C. burnetii were screened, this suggests that prioritizing antigens targeted by antibody responses is an efficient strategy to identify at least a subset of CD4(+) targets in large pathogens. Finally, we examined the nature of linkage between CD4(+) T cell and antibody responses in PI-WCV vaccinated mice. We found a surprisingly non-uniform pattern in the help provided by epitope specific CD4(+) T cells for antibody production, which can be specific for the epitope source antigen as well as non-specific. This suggests that a complete map of CD4(+) response targets in PI-WCV vaccinated mice will likely include antigens against which no antibody responses are made.
    Full-text Article · Mar 2011 · PLoS ONE
  • Source
    Steve D Swain · Nicole Meissner · Soo Han · Allen Harmsen
    [Show abstract] [Hide abstract] ABSTRACT: Infection with the opportunistic fungal pathogen Pneumocystis is assumed to pass without persistent pathology in immunocompetent hosts. However, when immunocompetent BALB/c mice were inoculated with Pneumocystis, a vigorous Th2-like pulmonary inflammation ensued and peaked at 14 days postinfection. This coincided with a 10-fold increase in the number of antigen-presenting cells (APCs) in the lung, and these cells were capable of presenting antigen in vitro, as well as greater uptake of antigen in vivo. When mice were presented with exogenous antigen at the 14-day time point of the infection, they developed respiratory sensitization to that antigen, in the form of increased airway hyperresponsiveness upon a later challenge, whereas mice not infected but presented with antigen did not. Like other forms of collateral sensitization, this response was dependent on interleukin-4 receptor signaling. This ability to facilitate sensitization to exogenous antigen has been previously reported for other infectious disease agents; however, Pneumocystis appears to be uniquely capable in this respect, as a single intranasal dose without added adjuvant, when it was administered at the appropriate time, was sufficient to initiate sensitization. Pneumocystis infection probably occurs in most humans during the first few years of life, and in the vast majority of cases, it fails to cause any overt direct pathology. However, as we show here, Pneumocystis can be an agent of comorbidity at this time by facilitating respiratory sensitization that may relate to the later development or exacerbation of obstructive airway disease.
    Full-text Article · Feb 2011 · Infection and immunity