Immunity and resistance to astrovirus infection

Astroviruses are one of the leading causes of acute viral enteritis in infants, and are recognized as a clinically important pathogen in the elderly and the immunocompromised. In spite of this, we still know very little about the immune response to astrovirus infection. Clinical observations and human volunteer studies have indicated a role for the humoral response and suggest neutralizing antibodies are important in limiting infection. Studies of human intestinal biopsies have suggested that cellular immunity; specifically CD4(+) T-cells may also be involved in the anti-astrovirus response. Additionally, various animal models have indicated potential roles for the innate immune system in controlling infections. How these various effector arms of the immune system collaborate to result in immunity and resistance to astrovirus infection is still unknown. This review summarizes our current understanding of the immune response to this pathogen and highlights the key concepts that still need to be addressed. Until we understand the role of the immune system in astrovirus infection or other enteric viruses, we will continue to be limited in our ability to treat and control gastrointestinal diseases.