[Obtention of monoclonal antibodies against human secretory IgA]

In order to determine the IgA levels in secretions, the authors engaged themselves to obtain monoclonal antibodies against this immunoglobulin and to show their possible utilization in the development of quantitation methods. 6 monoclonal antibodies were obtained: one against the secretory component (SC) and five against the heavy-chain (HC) of IgA. IgA purified from human colostrum was used as immunogen (HC). The immunoglobulin isotypes (IgG2a and IgG1) were determined in 2 monoclonal antibodies, one against SC and the other against HC. Polyacrylamide gel electrophoresis was performed in the presence of sodium dodecyl sulphate and b-mercapto-ethanol. Immunotransference was also carried out to determine their specificity. Secretory IgA was detected in saliva specimens. The anti-SC monoclonal antibody obtained in-the laboratory of the "Pedro Kourí" Institute of Tropical Medicine (IPK) was compared with a commercial one (Sigma Chemical Co.), and a similar behaviour was observed. The monoclonal antibody against SC (IPK) was used to detect IgA specific to LPS ogawa in persons vaccinated with an attenuated strain of Vibrio cholerae. Marked differences were found between the levels before and after immunization. The anti-HC monoclonal antibody was utilized to make an ELISA-like simulated system. The detection limit was 9.89 ng/mL.