DETECTION OF IGA ANTI-PGL-I SPECIFIC ANTIGEN TO MYCOBACTERIUM-LEPRAE IN MANGABEY MONKEYS INOCULATED WITH MYCOBACTERIUM-LEPRAE

Using sera from 4 pairs of mangabey monkeys inoculated with titrated d oses of Mycobacterium leprae we demonstrated that IgA antibodies again st M. leprae specific PGL-I antigen were present in 75% of inoculated monkeys' sera. High IgA antibody was detected in 50% (3/6) of infected animals and all three developed lepromatous leprosy (LL). Antibody ti ters correlated with PGL-I antigen in serum. The highest IgA peak appe ared late and corresponded to the beginning of treatment, and in two o f them appeared shortly after or corresponded with neurological damage . Low IgA response was found in the other 3 monkeys (50%-3/6), two of which developed indeterminate leprosy (I) and the other one LL. Low Ig A levels appeared late after IgG and IgM, and shortly after neurologic signs. Both I monkeys were negative for PGL-I in serum. The remaining 2 monkeys (25%-2/8) did not show an IgA response; one of them develop ed LL but the disease regressed to I. IgM seemed to correspond to the appearance of PGL-I in serum. The other animal did not develop clinica l symptoms of leprosy, and PGL-I in serum was negative. Although there was no clear relation between the development of anti-PGL-I IgA and e xperimental leprosy, the finding of a high IgA response in some animal s suggests that further studies are needed to evaluate the role of ant igen-specific IgA in the disease process.