ABSTRACT
A subpopulation of mononuclear cells from the circulating blood of normal human subjects has the ability to kill a wide spectrum of cultured tumor cells in vitro. Natural killer cell activity has been implicated as the first line of defense against both bacteria and viruses. Chandra and Wadhwa have noted that impaired local and systemic immunity in protein-calorie malnutrition can result in decreased secretory immunoglobulin A, fewer intraepithelial lymphocytes, and increased bacterial binding to epithelial cells and frequent gastrointestinal infection with decreased natural killer (NK) cell activity. While normal well-nourished infants produced a significant increase in NK cell activity following treatment with exogenous interferon in vitro, this was so in the marasmic children nor in children with kwashiorkor. The NK system is known to be immature at birth and to develop during the first few months of life. Alternatively, it may be that early demand on this population has led to paralysis of further response.
