Human Antibody Subclass ELISA

Our results have emphasized the potential involvement of the antibody-dependent cellular inhibition (ADCI) mechanism in the protective effect of antibodies mediating acquired immunity to Plasmodium falciparum malaria (1). The ADCI mechanism consists of a cooperation between monocytes and cytophilic antibodies able to bind to the Fc receptors present on the monocyte surface. Thus human IgG1 and IgG3 are the main isotypes effective in ADCI, whereas IgG2, IgG4, and IgM are ineffective and could rather have a blocking effect if they are directed to parasite antigens that are targets of effective antibodies (2-4). Therefore, in order to assess the potential role of a given parasite antigen in triggering protective immune responses, it is of interest to characterize the isotype distribution of antibodies directed to this antigen and elicited in protected versus nonprotected individuals.