rf might represent 1 : an extreme case of heteroclitic antibody , 2 : the internal image of a hypothetical fc-receptor reacting with rabbit igg but not with human igg , 3 : a result of polyclonal b cell activation , 4 : an antigenic crossreaction with an unknown antigen with similarities to rabbit igg but not to human igg .
C1155003
b cell activation
C0003320
antigenic