Effects of vitamin A deficiency on mucosal immunity and response to intestinal infection in rats.
OBJECTIVE
Vitamin A deficiency is associated with an increased incidence of infectious respiratory and alimentary tract diseases in children, and vitamin A supplementation can prevent and assist in treating these diseases. To clarify the mechanisms of these associations, we investigated the effects of vitamin A deficiency on mucosal immunity to intestinal infection in rats.


METHODS
Specific pathogen-free Sprague-Dawley rats received a vitamin A-free diet, with (n=20) or without (n=20) vitamin A supplementation. Intestinal infection was induced by oral inoculation of salmonella in 10 rats in each group. The rats were killed 3 d after infection was induced, and we measured the number, maturation, and activation of dendritic cells; the expression of Toll-like receptors 2 and 4; mRNA level of myeloid differentiation primary response gene (88) (MyD88, pattern-recognition receptors and their adapter protein); immune cytokine production in the intestinal mucosa; and the amount of secretory immunoglobulin A in the gut.


RESULTS
In vitamin-A deficient rats, the number of mucosal dendritic cells and the production of IL-12 markedly increased; the mucosal expressions of Toll-like receptor 2 and MyD88 were up-regulated, and secretions of interferon-γ and secretory immunoglobulin A were decreased. Infection aggravated the damage to the intestinal mucosa and lowered immunity in vitamin-A deficient rats.


CONCLUSIONS
Vitamin A deficiency damaged both humoral and cellular immunity in the mucosa. Modulation of dendritic cells is likely an important mechanism through which vitamin A deficiency affects mucosal immune responses against infection.
Yang
Yi
Y
Children's Hospital, Pediatrics Department, Fudan University, Shanghai, China.
Yuan
Yajie
Y
Tao
Yuehong
Y
Wang
Weiping
W
D000818:Animals; D003713:Dendritic Cells / Q000276:immunology; D019587:Dietary Supplements; D004195:Disease Models, Animal; D041981:Gastrointestinal Tract / Q000276:immunology* / Q000382:microbiology / Q000473:pathology; D018928:Immunity, Mucosal; D007070:Immunoglobulin A / Q000276:immunology; D007371:Interferon-gamma / Q000276:immunology; D018664:Interleukin-12 / Q000276:immunology; D007413:Intestinal Mucosa / Q000276:immunology* / Q000382:microbiology / Q000473:pathology; D053594:Myeloid Differentiation Factor 88 / Q000276:immunology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012141:Respiratory Tract Infections / Q000150:complications / Q000276:immunology* / Q000473:pathology; D012486:Salmonella typhimurium / Q000378:metabolism; D051195:Toll-Like Receptor 2 / Q000276:immunology; D014801:Vitamin A / Q000008:administration & dosage; D014802:Vitamin A Deficiency / Q000150:complications* / Q000276:immunology
D007070:Immunoglobulin A; C507781:Myd88 protein, rat; D053594:Myeloid Differentiation Factor 88; C495343:Tlr2 protein, rat; D051195:Toll-Like Receptor 2; D014801:Vitamin A; D018664:Interleukin-12; D007371:Interferon-gamma