Immune therapy for infectious diseases at the dawn of the 21st century: the past, present and future role of antibody therapy, therapeutic vaccination and biological response modifiers.

In the last decades of the 20th century, infectious diseases have re-emerged as a significant public health problem in the developed world. However, the available anti-infective armamentarium has proven to be alarmingly insufficient to combat many of the microbes that cause these diseases, such as drug resistant microbes, microbes for which therapy is not available or ineffective because of underlying host immune impairment, and microbes that only cause disease in the setting of impaired immunity but are not pathogens in normal individuals. Hence, there is an urgent need for new approaches to the treatment of infectious diseases that can increase the efficacy of anti-infective therapy and bolster the immune response to microbial agents in immunocompromised hosts, circumvent rising rates of antimicrobial drug resistance and be rapidly developed to fight emerging epidemics. Immune therapy, which encompasses pathogen-specific and non-pathogen specific modalities designed to augment or restore host immunity against disease causing microbes, are poised to play an important part in modern anti-infective therapy. Our growing understanding of host-microbe interaction and mechanisms of protective immunity have allowed for an increasingly rational approach to the design of immune based therapeutic modalities. As part of this effort, it is important to remember that the origin of modern anti-infective therapy was serum therapy, a pathogen-specific immune therapeutic modality. In this paper, we review the historical underpinnings and present and future applications of immune therapy for infectious diseases in light of current challenges to the field.