Role of antiviral antibodies in resistance against coxsackievirus B3 infection: interaction between preexisting antibodies and an interferon inducer

An experimental model of coxsackievirus B3 infection in newborn mice was utilized to examine the protective role of antiviral antibodies and an interferon inducer, polyinosinic acid-polycytidylic acid [poly(I:C)]. Subcutaneous administration to the infected mice of specific antiviral antibodies resulted in significant protection against coxsackievirus B3 infection. Antibody-treated animals had shortened viremia, early clearance of virus from tissues, and a reduced mortality rate. Dose response to antibodies was clearly demonstrated. However, the time of antibody administration in relation to the infection cycle was important. The protection was observed if antibodies were given before infection (24 h) or shortly after (2 h) infection. Administration of antibodies 24 h after infection resulted in no protection. The interferon inducer poly(I:C) prolonged the survival time of the infected mice, but this protective effect was incomplete and could only be demonstrated in animals treated before infection (24 h) or shortly after (2 h) infection. Enhanced protection against lethal coxsackievirus B3 infection was achieved in animals treated with a combination of antiviral antibodies and poly(I:C). These data confirm that antibody-mediated immunity plays a significant role in resistance against coxsackievirus B3 infection and suggest that antiviral antibodies may interact with poly(I:C) or work independently to produce an enhanced protective effect.