P. Puri et al., SPLENIC AND INTESTINAL LYMPHOCYTE-PROLIFERATION RESPONSE IN MICE FED MILK OR YOGURT AND CHALLENGED WITH SALMONELLA-TYPHIMURIUM, International journal of food sciences and nutrition, 47(5), 1996, pp. 391-398
Two groups of 4-5 week old DBA/2J Nii mice were put on either a yogurt
-based (n = 33) or a milk-based (n = 32) diet for a period of 4 weeks.
At the end of the feeding trial one sub group of mice each from the t
wo dietary groups was sacrificed for assessment of immune response. Th
e remaining mice were challenged intragastrically with 2 x 10(10) live
Salmonella typhimurium organisms and continued on their respective di
ets for 8 days after which they were also sacrificed. The immune respo
nse was measured by tritiated thymidine uptake by splenic or intestina
l lymphocytes in response to the mitogens concanavalin A (Con A), Phyt
ohaemaggutinin (PHA), and Lipopolysaccharide from Escherichia coli (LP
S). Serum Immunoglobulin A levels were also estimated. Feed efficiency
, measured as weight gain per unit energy intake, was significantly hi
gher for the yogurt diet than for the milk diet. The mitogenic respons
e of splenic and intestinal lymphocytes in the two groups of unchallen
ged mice was not different. In the Salmonella-challenged mice the stim
ulation index (SI) of splenic lymphocytes from yogurt-fed mice (mean /- SD) was significantly higher (P = 0.001) in response to Con A (24.7
1 +/- 3.40) than that of milk-fed mice (15.85 +/- 2.09). Further, in t
hese mice the SI of intestinal lymphocytes from yogurt-fed mice was hi
gher than that of milk-fed mice in response to Con A (7.35 +/- 0.61 vs
5.65 +/- 0.78, P = 0.016) and LPS (9.04 +/- 0.93 vs 6.15 +/- 1.32, P
= 0.016). Serum IEA levels in Salmonella-challenged mice were signific
antly higher 8 days after the challenge in the yogurt-fed group than i
n the milk-fed group (P < 0.001). The experiments indicate an improvem
ent in local gastrointestinal as well as systemic immunity on a yogurt
diet as compared to a milk diet.