Victoria Davenport

Publications of Victoria Davenport

• Neisseria lactamica selectively induces mitogenic proliferation of the naive B cell pool via cell surface Ig.

  Authors: Andrew T Vaughan, Louise S Brackenbury, Paola Massari, Victoria Davenport, Andrew Gorringe, Robert S Heyderman, Neil A Williams

  Journal of immunology (Baltimore, Md. : 1950). 09/2010; 185(6):3652-60.

  Neisseria lactamica is a commensal bacteria that colonizes the human upper respiratory tract mucosa during early childhood. In contrast to the closely related opportunistic pathogen NeisseriaNeisseria lactamica is a commensal bacteria that colonizes the human upper respiratory tract mucosa during early childhood. In contrast to the closely related opportunistic pathogen Neisseria meningitidis, there is an absence of adaptive cell-mediated immunity to N. lactamica during the peak age of carriage. Instead, outer membrane vesicles derived from N. lactamica mediate a B cell-dependent proliferative response in mucosal mononuclear cells that is associated with the production of polyclonal IgM. We demonstrate in this study that this is a mitogenic human B cell response that occurs independently of T cell help and any other accessory cell population. The ability to drive B cell proliferation is a highly conserved property and is present in N. lactamica strains derived from diverse clonal complexes. CFSE staining of purified human tonsillar B cells demonstrated that naive IgD(+) and CD27(-) B cells are selectively induced to proliferate by outer membrane vesicles, including the innate CD5(+) subset. Neither purified lipooligosaccharide nor PorB from N. lactamica is likely to be responsible for this activity. Prior treatment of B cells with pronase to remove cell-surface Ig or treatment with BCR-specific Abs abrogated the proliferative response to N. lactamica outer membrane vesicles, suggesting that this mitogenic response is dependent upon the BCR.

• T Cell Memory Response to Pneumococcal Protein Antigens in an Area of High Pneumococcal Carriage and Disease.

  Authors: Marianne W Mureithi, Adam Finn, Martin O Ota, Qibo Zhang, Victoria Davenport, Timothy J Mitchell, Neil A Williams, Richard A Adegbola, Robert S Heyderman

  The Journal of infectious diseases. 10/2009; 200(5):783-793.

  Background. Streptococcus pneumoniae is a leading cause of vaccine-preventable disease worldwide. Pneumococcal protein antigens are currently under study as components of potential vaccines thatBackground. Streptococcus pneumoniae is a leading cause of vaccine-preventable disease worldwide. Pneumococcal protein antigens are currently under study as components of potential vaccines that offer protection against multiple serotypes. We have therefore characterized T cell pneumococcal immunity acquired through asymptomatic carriage. Methods. Peripheral blood mononuclear cells from 40 healthy Gambian adults were stimulated with supernatants derived from S. pneumoniae strain (D39), 2 isogenic mutant strains lacking either pneumolysin or choline binding protein A, and recombinant pneumolysin. Immune responses were measured by cellular proliferation and by interleukin-10 (IL-10) and interferon-gamma (IFN-gamma) enzyme-linked immunosorbent spot and bioplex cytokine assays. Nasopharyngeal swabs were cultured to determine carriage rates. Results. S. pneumoniae nasopharyngeal carriage was detected in 60% of individuals. Both effector and resting (or central) CD4(+) T cell memory were frequently present to a range of pneumococcal antigens. However, the level of the effector memory response did not relate to current nasopharyngeal carriage. Pneumolysin was not immunodominant in these T cell responses but induced a distinct proinflammatory profile (high IFN-gamma, IL-12[p40], and L-17 levels and low IL-10 and IL-13 levels). Conclusions. In this population, T cell-mediated immunological memory potentially capable of pathogen clearance and immune surveillance is common but is not associated with the absolute interruption of pneumococcal carriage. How this naturally acquired immune memory influences pneumococcal vaccine efficacy remains to be determined.

• Absence of mucosal immunity in the human upper respiratory tract to the commensal bacteria Neisseria lactamica but not pathogenic Neisseria meningitidis during the peak age of nasopharyngeal carriage.

  Authors: Andrew T Vaughan, Andrew Gorringe, Victoria Davenport, Neil A Williams, Robert S Heyderman

  Journal of immunology (Baltimore, Md. : 1950). 03/2009; 182(4):2231-40.

  The normal flora that colonizes the mucosal epithelia has evolved diverse strategies to evade, modulate, or suppress the immune system and avoid clearance. Neisseria lactamica and NeisseriaThe normal flora that colonizes the mucosal epithelia has evolved diverse strategies to evade, modulate, or suppress the immune system and avoid clearance. Neisseria lactamica and Neisseria meningitidis are closely related obligate inhabitants of the human upper respiratory tract. N. lactamica is a commensal but N. meningitidis is an opportunistic pathogen that occasionally causes invasive disease such as meningitis and septicemia. We demonstrate that unlike N. meningitidis, N. lactamica does not prime the development of mucosal T or B cell memory during the peak period of colonization. This cannot be explained by the induction of peripheral tolerance or regulatory CD4(+)CD25(+) T cell activity. Instead, N. lactamica mediates a B cell-dependent mitogenic proliferative response that is absent to N. meningitidis. This mitogenic response is associated with the production of T cell-independent polyclonal IgM that we propose functions by shielding colonizing N. lactamica from the adaptive immune system, maintaining immunological ignorance in the host. We conclude that, in contrast to N. meningitidis, N. lactamica maintains a commensal relationship with the host in the absence of an adaptive immune response. This may prolong the period of susceptibility to colonization by both pathogenic and nonpathogenic Neisseria species.

• Impaired maintenance of naturally acquired T cell memory to the meningococcus in individuals with B cell immunodeficiency.

  Authors: Begonia Morales-Aza, Sarah J Glennie, Tomaz Pereira Garcez, Victoria Davenport, Sarah L Johnston, Neil A Williams, Robert S Heyderman

  Blood. 03/2009;

  The importance of T cells in the generation of antigen specific B cell immunity has been extensively described, but the role B cells play in shaping T cell memory is uncertain. In healthyThe importance of T cells in the generation of antigen specific B cell immunity has been extensively described, but the role B cells play in shaping T cell memory is uncertain. In healthy individuals, exposure to Neisseria meningitidis in the upper respiratory tract is associated with the generation of memory T cells in the mucosal and systemic compartments. However, we demonstrate that in B cell deficient subjects with X-linked agammaglobulinemia (XLA), naturally-acquired T cell memory responses to meningococcal antigens are reduced compared with healthy controls. This difference is not seen in T cell memory to an obligate respiratory pathogen, influenza virus. Accordingly, we show that meningococcal antigens upregulate MHC class II, CD40, CD86/80 expression on mucosal and systemic associated B cells and that antigen presentation stimulates T cell proliferation. A similar reduction in N. meningitidis but not influenza antigen-specific T cell memory was seen in subjects with X-linked hyper IgM syndrome (X-HIM), implicating the interaction of CD40-CD40L in this process. Together, these data implicate B cells in the induction and maintenance of T cell memory to mucosal colonizing bacteria such as N. meningitidis, and highlight the importance of B cells beyond antibody production but as a target for immune reconstitution.

• Mucosal immunity in healthy adults after parenteral vaccination with outer-membrane vesicles from Neisseria meningitidis serogroup B.

  Authors: Victoria Davenport, Eleanor Groves, Rachel E Horton, Christopher G Hobbs, Terry Guthrie, Jamie Findlow, Ray Borrow, Lisbeth M Naess, Philipp Oster, Robert S Heyderman, Neil A Williams

  The Journal of infectious diseases. 09/2008; 198(5):731-40.

  Nasopharyngeal carriage of meningococcus or related species leads to protective immunity in adolescence or early adulthood. This natural immunity is associated with mucosal and systemic T cellNasopharyngeal carriage of meningococcus or related species leads to protective immunity in adolescence or early adulthood. This natural immunity is associated with mucosal and systemic T cell memory. Whether parenteral Neisseria meningitidis serogroup B (MenB) vaccination influences natural mucosal immunity is unknown. To determine whether parenteral MenB vaccination affects mucosal immunity in young adults and whether this immunity differs from that induced in the blood. Otherwise healthy volunteers were immunized with MenB outer membrane vesicle vaccine before and after routine tonsillectomy. Mucosal and systemic immunity were assessed in 9 vaccinees and 12 unvaccinated control subjects by measuring mononuclear cell proliferation, cytokine production, Th1/Th2 surface marker expression, and antibody to MenB antigens. Parenteral vaccination induced a marked increase in systemic T cell immunity against MenB and a Th1 bias. In contrast, although mucosal T cell proliferation in response to MenB neither increased nor decreased following vaccination, mononuclear cell interferon gamma, interleukin (IL)-5, and IL-10 production increased, and the Th1/Th2 profile lost its Th1 bias. Parenteral MenB vaccination selectively reprograms preexisting naturally acquired mucosal immunity. As new-generation protein-based MenB vaccine candidates undergo evaluation, the impact of these vaccines on mucosal immunity in both adults and children will need to be addressed.

• Tonsil T cell immunity to human papillomavirus in the absence of detectable virus in healthy adults.

  Authors: Christopher G L Hobbs, Eleanor Groves, Victoria Davenport, Michael Bailey, Neil A Williams, Martin A Birchall, Robert S Heyderman

  The Laryngoscope. 04/2008; 118(3):459-63.

  BACKGROUND: Human papillomavirus (HPV) is known to infect the epithelium of the upper aerodigestive tract; however, major questions regarding prevalence and persistence of infection, and theirBACKGROUND: Human papillomavirus (HPV) is known to infect the epithelium of the upper aerodigestive tract; however, major questions regarding prevalence and persistence of infection, and their relation to local immune response, remain unanswered. OBJECTIVES: To evaluate the tonsil T cell immune response to HPV and compare this to the frequency of detectable virus at this site. STUDY DESIGN: A cross-sectional study of cancer-free adults undergoing routine tonsillectomy. METHODS: Mucosal immune responses to recombinant HPV16 L2E6E7 and HPV6 L2E7 antigens were measured by tonsillar T-lymphocyte proliferation assay in 13 subjects. HPV deoxyribonucleic acid (DNA) was assessed by PCR and reverse line-blot hybridization in an expanded population of 44 subjects. RESULTS: Proliferative T-cell responses to HPV16 and HPV6 were identified in all patients. The presence of a CD45RO+ T cell population responsive to HPV6 L2E7 was confirmed in three of six subjects tested. There were no CD45RO+ responses to HPV16 L2E6E7 and no evidence of current or latent HPV infection of the tonsil. CONCLUSIONS: T cell memory to human papillomavirus can be identified in tonsil tissue from an adult population in the absence of concurrent HPV infection. How novel HPV vaccines might augment this preexisting cell-mediated immunity is an essential area for investigation.

• Regulation of Th-1 T cell-dominated immunity to Neisseria meningitidis within the human mucosa.

  Authors: Victoria Davenport, Eleanor Groves, Christopher G Hobbs, Neil A Williams, Robert S Heyderman

  Cellular microbiology. 05/2007; 9(4):1050-61.

  Neisseria meningitidis is commonly carried asymptomatically in the upper respiratory tract and only occasionally invades the bloodstream and meninges to cause disease. Naturally acquired immunityNeisseria meningitidis is commonly carried asymptomatically in the upper respiratory tract and only occasionally invades the bloodstream and meninges to cause disease. Naturally acquired immunity appears protective but the nature of the cellular immune response within the mucosa is uncertain. We show that following in vitro stimulation with N. meningitidis serogroup B (MenB) antigens, approximately 66% of the dividing mucosal CD4(+)CD45RO(+) memory population express the Th1-associated IL18-R while the remainder express CRTH2, a Th2-associated marker. The pro-inflammatory bias of this anti-MenB response is not evident in blood, demonstrating compartmentalization at the induction site; and occurs in the presence or absence of lipopolysacharide indicating that these responses are already fully committed. Depletion of CD25(+) cells reveals suppression of the effector CD4(+) T cell response restricted to the mucosa and most marked in children (i.e. those at greatest risk of disease). Mucosal T-regulatory cell (Treg) activity is partially overcome by blocking the human glucocorticoid-induced TNF receptor (GITR) and is not seen following stimulation with antigens from another mucosal pathogen, influenza virus. Pro-inflammatory, antimeningococcal T cell responses may limit invasive disease at the mucosa but Treg induction while reducing immunopathological damage, may also restrict the effectiveness of the protective response, particularly in children.

• Mucosal immunity and optimizing protection with meningococcal serogroup B vaccines.

  Authors: Robert S Heyderman, Victoria Davenport, Neil A Williams

  Trends in microbiology. 03/2006; 14(3):120-4.

  Candidate Neisseria meningitidis serogroup B vaccines that are based on outer-membrane vesicles induce protective immunity in adults but provide neither crossprotection for infants nor long-lastingCandidate Neisseria meningitidis serogroup B vaccines that are based on outer-membrane vesicles induce protective immunity in adults but provide neither crossprotection for infants nor long-lasting immunity. We suggest that this lack of vaccine efficacy is not solely because the best antigens are yet to be identified but also results from inappropriate programming of the immune response. Natural carriage of N. meningitidis and related bacteria leads to the development of protective immunity both at the mucosal surface and in the circulation. We propose that vaccine strategies that mimic this natural immunization process would better-optimize vaccine-induced protective immunity. Thus, mucosal immunization before a systemic booster vaccination could provide the solution and reduce the necessity for multiple injections to achieve immunity.

• Parenteral influenza vaccination influences mucosal and systemic T cell-mediated immunity in healthy adults.

  Authors: Terry Guthrie, Christopher G L Hobbs, Victoria Davenport, Rachel E Horton, Robert S Heyderman, Neil A Williams

  The Journal of infectious diseases. 01/2005; 190(11):1927-35.

  We sought to determine whether palatine tonsils (PTs) harbor naturally acquired influenza-specific T cell immunity and whether routine parenteral immunization with influenza vaccine influencesWe sought to determine whether palatine tonsils (PTs) harbor naturally acquired influenza-specific T cell immunity and whether routine parenteral immunization with influenza vaccine influences mucosal and systemic T cell reactivity. We demonstrate that tonsillar and peripheral blood mononuclear cells (PBMCs) proliferate strongly to influenza antigens, suggesting that naturally acquired immunity exists within both the mucosal and systemic compartments. Influenza vaccination induced significantly stronger T cell responses in both PTs and blood, in addition to increasing titers of anti-influenza antibodies in serum and saliva. More-rapid proliferative responses of PTs after vaccination were associated with a shift from a response involving both CD45RA+ and CD45RO+ T cells to an entirely CD45RO+-dependent response. Interestingly, the ratio of interferon- gamma to interleukin-5 was dramatically higher in cultures of PT T cells responding to influenza than in PBMCs. Our data indicate that parenteral influenza vaccination influences both mucosal and systemic naturally acquired T cell immunity.

• Evidence for naturally acquired T cell-mediated mucosal immunity to Neisseria meningitidis.

  Authors: Victoria Davenport, Terry Guthrie, Jamie Findlow, Ray Borrow, Neil A Williams, Robert S Heyderman

  Journal of immunology (Baltimore, Md. : 1950). 11/2003; 171(8):4263-70.

  Naturally acquired protective immunity against Neisseria meningitidis is thought to partially explain the disparity between the high levels of carriage in the human nasopharynx and the rare incidenceNaturally acquired protective immunity against Neisseria meningitidis is thought to partially explain the disparity between the high levels of carriage in the human nasopharynx and the rare incidence of disease. To investigate this immunity to Neisseria meningitidis at the mucosal level, in vitro cellular responses to outer membrane vesicle preparations derived from this pathogen were examined using mononuclear cells from the palatine tonsils of adults and children. Characterization of these responses was achieved by depletion of CD45RA(+), CD45RO(+), and CD19(+) populations and outer membrane vesicles derived from isogenic mutants expressing different serosubtypes of the major outer membrane protein, porin A (PorA), no PorA and membrane preparations from a mutant with no LPS (LpxA(-)). The magnitude of cellular proliferative responses against the outer membrane vesicles were strongly associated with age and were largely T cell mediated, involving both CD45RO(+) and CD45RA(+) T cell phenotypes. Responses were not dependent on LPS but consisted of both PorA cross-specific and non-PorA-dependent responses. Cellular immunity against Neisseria meningitidis was found to be frequently associated with systemic IgG Abs but was not associated with serum bactericidal Abs. For the first time our results demonstrate an age-associated acquisition of mucosal T effector/memory cell responses to Neisseria meningitidis. This mucosal cellular immunity can be present in the absence of serum bactericidal Abs, a classical marker of protective immunity.

• Mucosal immunity and optimizing protection with meningococcal serogroup B vaccines

  Authors: Robert S. Heyderman, Victoria Davenport, Neil A. Williams

  Trends in Microbiology.

  Candidate Neisseria meningitidis serogroup B vaccines that are based on outer-membrane vesicles induce protective immunity in adults but provide neither crossprotection for infants nor long-lastingCandidate Neisseria meningitidis serogroup B vaccines that are based on outer-membrane vesicles induce protective immunity in adults but provide neither crossprotection for infants nor long-lasting immunity. We suggest that this lack of vaccine efficacy is not solely because the best antigens are yet to be identified but also results from inappropriate programming of the immune response. Natural carriage of N. meningitidis and related bacteria leads to the development of protective immunity both at the mucosal surface and in the circulation. We propose that vaccine strategies that mimic this natural immunization process would better-optimize vaccine-induced protective immunity. Thus, mucosal immunization before a systemic booster vaccination could provide the solution and reduce the necessity for multiple injections to achieve immunity.