Potential immunomodulation by nutritional excesses and deficiencies can act as cofactors in human immunodeficient virus infection. The role of nutrition in the development and expression of acquired immunodeficiency syndrome (AIDS) is suggested and evaluated. LP-BM5 murine retroviral infection causes immune changes yielding an acquired immune deficiency syndrome with functional similarities to human AIDS. The value of the murine AIDS model to evaluate, rapidly, immune changes caused by potential cofactors, including nutritional changes, is illustrated.