T cell responses and cytokine production requires recognition of antig
enic peptides/MHC by the TCR/CD3 complex and reception of APC costimul
atory signals through the CD28 counter-receptors. Protein malnutrition
(PM) alters T cell immune responses and decreases resistance to infec
tion. To determine the effect of PM on T cell cytokine production, int
erferon-gamma (IFN)-gamma, interleukin (IL)-2 and IL-4 production by s
plenic T cells from mice fed either a moderately protein deficient die
t (4% casein) or a diet sufficient in protein (20% casein) in response
to ConA or anti-CD3 was measured. The production of IL-4 was signific
antly decreased while production of IL-2 was increased from T cells of
PM mice during co-culture with native APC. To determine the effect of
PM on costimulatory and counter-receptor signals, T cells were stimul
ated with Concanavalin A (ConA) and costimulated with native APC, with
APC from the reciprocal dietary group, or with antibody to CD28. APC
from PM mice co-cultured with T cells of control mice retained a norma
l ability to costimulate,control T cell cytokine production. However p
urified T cells from PM mice produced significantly less cytokines whe
n co-cultured with control APC.,In the absence of APC but in the prese
nce of artificial costimulation by anti-CD28, the production of IL-2 a
nd IL-4 from enriched T cells of PM mice was significantly decreased c
ompared with T cells from control mice. Thus, the T cell counter-recep
tor pathway is significantly impaired, while APC costimulatory functio
n remains normal. during PM. Copyright (C) 1996 Elsevier Science Inc.