RESUMO
The appearance of cells (CFC) having the property to cluster several layers of sheep red blood cells around themselves has been used in our laboratory as a marker for T cell activation. In this study, enumeration of stimulated T cells was carried out by this technique, whereas enumeration of B cells was carried out with surface Ig staining using fluorescein-labelled anti-Ig antibodies or F(ab)2 anti-Ig. Lymphocytes were stimulated in vitro for various lengths of time with the polyclonal mitogen PWM, the specific antigen Varidase and LPS added at culture initiation or 16 hours after beginning of culture. Our results confirm that human lymphocytes preincubated for 16 hours before addition of LPS give rise to higher numbers of CFC and blast cells, In all cases, less than half of these blasts reacted with the F(ab)2 anti-Ig, This suggests that under these conditions, LPS is not a mitogen specific for human B cells.
