title: Exposure to Leishmania major modulates the proportion of CD4+ T cells without affecting cellular immune responses.
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-gamma 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-gamma 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-gamma 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-gamma production are increased in exposed individuals.
authors.affiliation: Immunology Department, Pasteur Institute of Iran, Pasteur Avenue 69, Tehran, Iran. mhalimohammadian@yahoo.com
authors.forename: Mohammad Hossein
authors.initials: MH
authors.lastname: Alimohammadian
authors.forename: Haiedeh
authors.initials: H
authors.lastname: Darabi
authors.forename: Shirin
authors.initials: S
authors.lastname: Malekzadeh
authors.forename: Hamid
authors.initials: H
authors.lastname: Mahmoodzadeh-Niknam
authors.forename: Soheila
authors.initials: S
authors.lastname: Ajdary
authors.forename: Ali
authors.initials: A
authors.lastname: Khamesipour
authors.forename: Ahmad
authors.initials: A
authors.lastname: Bahonar
authors.forename: Alireza
authors.initials: A
authors.lastname: Mofarrah
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000382:microbiology*; D018849:Controlled Clinical Trials as Topic; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000096:biosynthesis; D007694:Killer Cells, Natural / Q000276:immunology; D018320:Leishmania major / Q000276:immunology*; D054332:Leishmaniasis Vaccines / Q000008:administration & dosage / Q000276:immunology; D016773:Leishmaniasis, Cutaneous / Q000276:immunology* / Q000469:parasitology / Q000517:prevention & control; D008213:Lymphocyte Activation / Q000276:immunology; D008297:Male; D008875:Middle Aged; D012882:Skin Tests
chemical_list: D054332:Leishmaniasis Vaccines; C416262:autoclaved Leishmania major vaccine; D007371:Interferon-gamma