Passive antibody
immunotherapy (PAI) for
cryptosporidiosis is a treatment strategy that has been actively pursued in laboratory studies and early-stage clinical studies for the last decade. Several experimental approaches have been initiated, including use of bovine colostrum and colostral
antibodies (hyperimmune and natural),
monoclonal antibodies, chicken egg yolk
antibodies, and even orally administered human plasma
antibodies. Most studies have employed
oral administration to treat or prevent this intestinal
infection. The interest in this treatment strategy has been sparked by the lack of an effective or approved
therapy, increased awareness of the widespread nature of this parasite, epidemiological evidence that humoral immunity plays an important role in host resistance, and several early case reports of antibody
therapy in which remarkable resolution of the disease was observed. Most studies using a variety of preparations of
antibodies administered to animals and humans have shown some degree of efficacy, though the responses have been, for the most part, partial rather than complete resolution of the disease. This chapter examines critically the scientific rationale and the evidence for PAI for
cryptosporidiosis, including practical considerations and future approaches.