IFN-gamma and delayed-type hypersensitivity are associated with cutaneous leishmaniasis in vervet monkeys following secondary rechallenge with Leishmania major.
IFN-gamma levels and delayed-type hypersensitivity (DTH) responses were evaluated in vervet monkeys, following secondary infection with Leishmania major (L. major). The animals had previously been vaccinated with leishmanial antigen, exposed to a primary infection and allowed to self-cure. Supernatants of peripheral blood mononuclear cell (PBMC) cultures, stimulated with either L. major antigen or Concanavalin A (Con A), were examined for the presence of IFN-gamma in a double sandwich enzyme-linked immunosorbent assay (ELISA). Significant levels of IFN-gamma were detected during active disease and following self-cure in both antigen and Con A supernatants. Higher levels of IFN-gamma were, however, present during active disease as compared with after self-cure. Positive and strong DTH responses were elicited in all experimental animals, following intradermal injection of fixed promastigotes (5 x 10(7)/animal) before rechallenge, during active infection and following self-cure. Again, strongest DTH responses were obtained during active infection as compared with the other sampling points. There was a correlation between IFN-gamma levels and DTH responses. It was concluded that IFN-gamma secretion and positive DTH responses are associated with secondary L. major infection and represent specific immunological correlates of protection in this disease model.
Olobo
J O
JO
Institute of Primate Research, National Museums of Kenya, Nairobi.
Reid
G D
GD
Githure
J I
JI
Anjili
C O
CO
D000818:Animals; D002522:Chlorocebus aethiops; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006968:Hypersensitivity, Delayed / Q000209:etiology*; D007371:Interferon-gamma / Q000032:analysis / Q000096:biosynthesis*; D007895:Leishmania tropica; D016773:Leishmaniasis, Cutaneous / Q000276:immunology*; D008297:Male
D007371:Interferon-gamma