Exposure to Leishmania Major Modulates the Proportion of Cd4+ T Cells Without Affecting Cellular Immune Responses Publisher Pubmed



Alimohammadian MH^{1, 4} ; Darabi H¹ ; Malekzadeh S¹ ; Mahmoodzadehniknam H¹ ; Ajdary S¹ ; Khamesipour A² ; Bahonar A³ ; Mofarrah A³
Source: Microbiology and Immunology Published:2007

Abstract

The immune responses of individuals exposed to Leishmania major were evaluated and compared with those of non-exposed volunteers. Forty-one patients with active lesion(s), 43 healed individuals, 15 vaccinees 1 month or 1 year post vaccination, and 15 non-exposed volunteers were studied. Leishmanin skin test (LST) response, proliferative response of lymphocyte (PRL) to L. major antigen, IFN-γ and IL-4 production, and percentage of L. major-specific CD4+, CD8+ and CD16+/CD56+ cells in peripheral blood mononuclear cells were assessed. Data showed positive LST (>5 mm) in 92% of patients, 98% of healed, and 80% or 43% of vaccinees 1 month and 1 year post vaccination, respectively. Positive PRL (SI>2.5) was displayed in 90%, 84%, 46% and 7% of patients, healed, vaccinated (post 1 year) and non-exposed donors, respectively. The mean ±S.E. of IFN-γ was 924 ± 149, 1,278 ± 185, 470 ± 282 or 258 ± 82 pg/ml in patients, healed cases and vaccinees after 1 month or 1 year, respectively. Positive IFN-γ responders (>300 pg/ml) were shown in 72% of patients, 81% of healed cases, 31% or 39% of vaccinees and 0% of non-exposed donors. A reduced percentage of CD4+ T-cells and an increased percentage of NK cells were found in exposed individuals compared to non-exposed donors. The data indicated that exposure to L. major modulates the proportion of CD4+ T cells and increases NK cells percentage. However, the cellular immune responses including induction of LST, and IFN-γ production are increased in exposed individuals.