H Keshavarz-Valian

Publications of H Keshavarz-Valian

• Differential in vitro CD4+/CD8+ T-cell response to live vs. killed Leishmania major.

  Authors: M Nateghi Rostami, H Keshavarz Valian, S E Eskandari, A Miramin Mohammadi, S T Shahrestani, A Sarraf-Nejad, A Khamesipour

  Parasite immunology. 02/2010; 32(2):101-10.

  Clinical trials of killed Leishmania vaccines showed a limited efficacy compared with leishmanization (LZ). The reason for this difference in protection against cutaneous leishmaniasis (CL) is notClinical trials of killed Leishmania vaccines showed a limited efficacy compared with leishmanization (LZ). The reason for this difference in protection against cutaneous leishmaniasis (CL) is not known and in vivo studies on T-cell function may provide valuable information. Nevertheless, there are limited studies on the nature of the stimulatory effects of live vs. killed parasites on human T cells in vitro. A total of nine Leishmanin Skin Test+ volunteers with a history of self-healing CL (HCL) and seven healthy volunteers were included in this study. 5,6-carboxyfluroescein diacetate succinimidyl ester-labelled CD4(+)/CD8(+) lymphocytes were cultured with killed Leishmania Lysate (Killed LL) or live Leishmania major (Live LM) and analysed for proliferation using flow cytometry. Culture supernatants were used for cytokine titration. In HCL volunteers, upon stimulation with killed LL, the number of proliferated CD4(+)/CD8(+) cells was significantly more than that of unstimulated (P < 0.001) or live LM stimulated (P < 0.05) cells, or cells from controls (CD4(+)/CD8(+): P < 0.05/P < 0.001). Stimulation of CD4(+) cells with Live LM (P < 0.001) or Killed LL (P < 0.05) induced a significantly higher IFN-gamma production compared with that of controls, but Live LM induced significantly (P < 0.05) more IFN-gamma than Killed LL. A significantly (P < 0.05) higher IFN-gamma production was observed when CD8(+) cells were stimulated with Live LM. Cells from HCL volunteers showed significantly more IL-10 production to Live LM stimulation compared with that of controls (CD4(+): P < 0.05 /CD8(+): P < 0.001) or cells stimulated with Killed LL (CD4(+)/CD8(+): P < 0.001/P < 0.0005). Whereas Killed LL induced more proliferation response in purified T cells, Live LM induced cytokine production without significant induction of proliferation. The results from healed CL volunteers in this study could be implicated in further studies on T-cell response in vaccinated individuals.

• Isolation and molecular characterization of Toxoplasma gondii strains from different hosts in Iran.

  Authors: N Zia-Ali, A Fazaeli, M Khoramizadeh, D Ajzenberg, M Dardé, H Keshavarz-Valian

  Parasitology research. 07/2007; 101(1):111-5.

  Toxoplasma gondii is one of the most prevalent protozoan parasites in Iran. This study was aimed to isolate T. gondii from a variety of hosts and to genetically analyze the parasite isolates. TheToxoplasma gondii is one of the most prevalent protozoan parasites in Iran. This study was aimed to isolate T. gondii from a variety of hosts and to genetically analyze the parasite isolates. The prevalence of T. gondii in different animal hosts was assessed in two provinces of Iran, Tehran and Mazandaran in the central and northern parts, respectively. The latex agglutination (LA) test was carried out, and antibodies were found in 24 out of 105 sheep, 5 out of 35 goats, 23 out of 45 free-ranging chickens (Gallus domesticus), 2 out of 13 ducks (Anas spp.), and two of four stray cats (Felis domesticus). T. gondii was isolated by bioassay in mice from four sheep, six chickens, one duck, two cats, and three human samples. Genotyping of these 16 isolates was performed using Multiplex PCR for five microsatellite markers and GRA6 gene sequence analysis. The results indicated that the studied isolates consisted of only two genotypes, II and III, with no evidence of type 1 or mixed genotypes.

• Effects of p-aminobenzoic acid, methionine, threonine and protein levels on susceptibility of mice to Plasmodium berghei.

  Authors: H Keshavarz-Valian, N E Alger, G A Boissonneault

  The Journal of nutrition. 01/1986; 115(12):1613-20.

  The effects of dietary p-aminobenzoic acid (PABA), protein, methionine and threonine on Plasmodium berghei infection in mice were investigated. Animals were fed diets containing 12 or 20% caseinThe effects of dietary p-aminobenzoic acid (PABA), protein, methionine and threonine on Plasmodium berghei infection in mice were investigated. Animals were fed diets containing 12 or 20% casein supplemented with PABA (0 or 2 mg/kg diet), methionine (0 or 15 mg/g casein) and threonine (0, 7.5, 27.5 or 47.5 mg/g casein). Percent mortality was lower in rats fed diets without PABA than in those fed diets containing PABA. All further experiments were conducted without supplemental PABA. While the mean day of death was greater in the groups fed 12% casein, percent mortality in these groups was nearly twofold higher than in the groups fed 20% casein. The presence or absence of 15 mg methionine per gram casein had no effect on percent mortality, mean day of death, or percent parasitemia, regardless of dietary casein level. Supplementation of threonine at any level to the 12% casein diet with supplemental methionine resulted in mortality rates similar to those from animals fed the 20% casein diets, but percent mortality was not altered by threonine in the absence of supplemental methionine. The mean day of death of animals fed 20% casein increased with increments of added threonine. Methionine had no influence on this phenomenon. It is concluded that the quantity of dietary protein and the quality of its amino acid composition can have profound effects on the susceptibility of mice to malaria.

• Plasmodium berghei: the effects of suppressor factor on vaccination.

  Authors: N E Alger, H Keshavarz-Valian

  International journal for parasitology. 07/1984; 14(3):301-7.

• Malaria vaccine antigen(s): detergent solubilization, partial isolation, and recovery of immunoprotective activity.

  Authors: L E D'Antonio, H Keshavarz-Valian, N E Alger

  Infection and immunity. 02/1984; 43(1):442-4.

  Plasmodium berghei-infected erythrocytes were solubilized with the nonionic detergent n-octyl glucoside and membrane-containing P. berghei fragments with either n-octyl glucoside or the ionicPlasmodium berghei-infected erythrocytes were solubilized with the nonionic detergent n-octyl glucoside and membrane-containing P. berghei fragments with either n-octyl glucoside or the ionic detergent sodium deoxycholate. Unsolubilized material was separated by centrifugation, and the detergent was removed from the respective supernatants by gel filtration. Reaggregated components in the respective void volume eluates acted as a specific vaccine in recipient mice, resulting in a dose-related accelerated elimination of infection and increased survival after challenge with the homologous parasite.