Leishmania chagasi antigens recognized in cured visceral leishmaniasis and asymptomatic infection

A. C. White, M. Castes, L. Garcia, D. Trujillo, L. Zambrano

Research output: Contribution to journalArticle

27 Scopus citations

Abstract

Active visceral leishmaniasis is associated with antigen-specific immunosuppression. However, cured patients develop a cellular immune response associated with resistance to reinfection. Recent studies have identified patients with asymptomatic or subclinical infections, which are also accompanied by an immune response. In order to identify subjects immune to Leishmania chagasi, we performed a skin-test survey in an endemic area in eastern Venezuela. The delayed-type hypersensitivity (DTH) response was assessed in patients cured of visceral leishmaniasis, as well as in their relatives and neighbors. Of the latter, 36 (34.2%) of 105 were positive and 26 (24.7%) of 105 gave intermediate responses. The DTH reaction correlated with age. The antigens recognized by a subgroup of cured patients, those with positive skin-test results, and controls (skin-test negative) were assessed by Western blotting with sera, and T cell immunoblotting with peripheral blood mononuclear cells. No consistent differences between the groups were noted in Western blots with L. chagasi antigens. T cell blots were performed on five patients from each group. For the cured patients and skin-test positive contacts, a significant proliferative response to fraction 12 (< 20.5 kDa) was noted in four of five patients in each group. Cells from three of five cured patients and two of five skin-test-positive patients proliferated in response to fraction 4 (73-115 kDa). The response to other fractions was variable, with only a minority of patients responding to any one fraction. These data suggest that the antigens recognized by patients with evidence of immunity to L. chagasi are quite variable. However, response to antigens in fraction 12 (≤ 20.5 kDa) was noted in most patients, and could be of significance in protective immunity.

Original languageEnglish (US)
Pages (from-to)123-131
Number of pages9
JournalAmerican Journal of Tropical Medicine and Hygiene
Volume46
Issue number2
DOIs
StatePublished - Jan 1 1992
Externally publishedYes

ASJC Scopus subject areas

  • Parasitology
  • Virology
  • Infectious Diseases

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