IDENTIFICATION OF MONOCLONAL-ANTIBODIES FOR IMMUNOHISTOCHEMICAL STAINING OF FELINE B-LYMPHOCYTES IN FROZEN AND FORMALIN-FIXED PARAFFIN-EMBEDDED TISSUES

Commercially-available monoclonal antibodies to B lymphocytes were eva luated for immunohistochemical staining of feline B lymphocytes in fro zen and formalin-fixed, paraffin-embedded tissues using an avidin biot in complex immunoperoxidase immunohistochemical technique, Three monoc lonal antibodies: F46A and F72A raised to ''carnivore'' B lymphocytes and RA3.6B2 raised to murine B lymphocytes, stained B lymphocyte-depen dent areas of frozen feline lymphoid tissue. In addition, antibody RA3 .6B2 stained B lymphocyte dependent areas in formalin-fixed, paraffin- embedded feline tissues, There was no staining of T lymphocyte-depende nt areas in either frozen or formalin-fixed tissues. Dual parameter fl ow cytometry, using an anti-pan-T lymphocyte antibody, revealed that g reater than 99% of the cells stained by RA3.6B2 are a population disti nct from T lymphocytes. F46A was shown to stain a sub-population of th ose cells stained with RA3.6B2, These antibodies may be useful in the identification of feline B lymphocytes using immunohistochemistry and flow cytometry and thereby provide additional tools to study B lymphoc yte ontogeny and the significance of lymphocyte phenotype in lymphoid neoplasia in cats.