DISTRIBUTION OF MONOCLONAL-ANTIBODIES IN INTESTINAL AND UROGENITAL SECRETIONS OF MICE BEARING HYBRIDOMA BACKPACK TUMORS

Mice bearing IgA hybridoma 'backpack' rumours have been used to demons trate that secretion of a single monoclonal IgA can protect against mu cosal infection, but the relevance of this model to normal IgA protect ion is not clear. The authors analysed the distribution of specific mo noclonal and total antibodies in bile, local intestinal secretions, ce rvical-vaginal secretions, urine and serum of mice bearing anti-choler a toxin (CT) IgA and IgG backpack rumours, with and without bile duct ligation. Backpack tumours resulted in high levels of both anti-CT and total IgA or IgG in serum, and IgA (but not IgG) in bile. Secretions recovered by absorbent filter 'wicks' from mucosal surfaces throughout the intestines of backpack tumour mice contained significant concentr ations of monoclonal anti-CT IgA, but total IgA levels were as in norm al mice. Neither monoclonal nor total IgA levels on mucosal surfaces w ere altered by bile duct ligation. Furthermore, anti-CT monoclonal IgA levels in local intestinal secretions of backpack tumour mice were co mparable to specific polyclonal IgA levels previously elicited by muco sal immunization with CT. Thus, IgA-mediated protection against enteri c challenge in the backpack tumour model may be a valid predictor of p rotection provided by natural mucosal immunization in vivo. High monoc lonal IgA levels in bile, urine and the female genital tract, however, may not reflect the situation in normal immunized mice.