the injection of chicken and sheep red blood cells ( crbc and srbc ) into rat popliteal lymph nodes either together or sequentially 2 , 4 , 6 , or 8 days apart resulted in an enhanced immune response when the second antigen was injected 2 or 4 days after the injection of the first antigen ( antigenic promotion ) or a suppressed immune response when the second antigen was injected 6 days after the injection of the first antigen ( antigenic competition ) .
C0301872
immune response
C0003320
antigen