G10.3 monoclonal antibody identifies novel functional cell surface structures expressed by normal B lymphocytes and various malignant cell lines

G10.3, a unique monoclonal antibody (mAb), was produced to better character ize lymphocyte subsets. In the present study, we show that this mAb identif ies 118, 83 and 51 kDa cell surface sialylated glycoproteins on the immuniz ing cell line YTindi. The reactivity of G10.3 mAb is restricted in normal c ells to B lymphocytes, whereas within tumoral cell lines various lymphoid a nd non-lymphoid cells were found positive. Interestingly, functional studie s revealed that triggering G10.3 mAb reactive molecules with soluble antibo dy led tu an inhibition of growth and to an induction of programmed cell de ath in tumor cell lines expressing high levels oi reactive molecules.