the signal requirement for polyclonal b cell responses in the presence of t helper ( th ) cells , lipopolysaccharide ( lps ) , anti-ig antibodies coupled to sepharose beads ( anti-ig ) and/or t cell supernatants ( sn ) was studied in a murine system using ( a ) low numbers of b cells/culture in order to reduce the effects of contaminating th cells and ( b ) defined sources of irradiated filler cells in the form of el4 thymoma cells or cloned male h-y antigen-specific th cells .
C0037083
the signal
C0007634
cells