Study of cross-reactivity of Mycobacterium leprae reactive salivary IgA with other environmental mycobacteria.
Majority of the endemic population is exposed to Mycobacterium leprae but very few develop disease. Humoral mucosal immune response mediated through M. leprae reactive salivary antibodies has been suggested to be quite important in the protective immunity. As the endemic population is also exposed to many environmental mycobacteria, we tested saliva from 121 subjects for the cross-reactivity of the M. leprae reactive salivary antibodies to mycobacteria like M. smegmatis and M. phlei. Saliva samples were treated with these two mycobacteria prior to testing M. leprae reactive antibodies by ELISA. In 59 subjects (48.76%), original and cross-reacted saliva showed same absorbance values suggesting no cross-reactivity. 26 subjects (21.49%) showed less than 25% drop in the OD values whereas 21 subjects (17.4%) showed 25% to 50% drop after reacting saliva with the mycobacteria. 15 subjects (12.4%) showed more that 50% drop in OD. The data suggest that though in half of subjects antibodies did not cross-react with mycobacteria tested, there were subjects where antibodies showed cross-reactivity to mycobacteria suggesting that positive salivary M. leprae reactive IgA response could be to some extent due to exposure to environmental mycobacteria and it could also be protective against M. leprae.
Kamble
R R
RR
Stanley Browne Laboratory, TLM Community Hospital, Nand Nagari, Delhi-110093, India.
Shinde
V S
VS
Madhale
S P
SP
Jadhav
R S
RS
D000907:Antibodies, Bacterial / Q000032:analysis / Q000276:immunology; D000917:Antibody Formation; D003429:Cross Reactions / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007070:Immunoglobulin A / Q000032:analysis* / Q000276:immunology; D009166:Mycobacterium leprae / Q000276:immunology* / Q000302:isolation & purification; D012463:Saliva / Q000737:chemistry / Q000276:immunology
D000907:Antibodies, Bacterial; D007070:Immunoglobulin A