The immuno-modulatory role of dietary lutein in domestic cats is unknown. F
emale Tabby cats (10-month old, n=56) were supplemented daily for 12 weeks
with 0, 1, 5 or 10 mg lutein. Blood was collected on Weeks 0, 2, 4, 8 and 1
2 to assess the following: (1) mitogen-induced peripheral blood mononuclear
cells (PBMCs) proliferation, (2) changes in PBMC subpopulations, (3) inter
leukin-2 (IL-2) production and (4) plasma immunoglobulin (Ig)G production,
in addition, delayed-type hypersensitivity (DTH) response to concanavalin A
(Con A) or a polyvalent vaccine was performed on Weeks 0, 6 and 12. Dietar
y lutein increased plasma lutein concentrations in a dose-dependent manner
(p<0.001) and concentrations had not reached steady state after 12 weeks of
feeding in cats given 5 or 10 mg lutein. Concentrations of plasma retinol
and a-tocopherol were not influenced by diet. The DTH response to vaccine b
ut not to Con A increased (p<0.05) in a dose-dependent manner on Week 6. Co
mpared to control, cats fed lutein also showed enhanced Con A- and pokeweed
mitogen-stimulated PBMCs proliferation. Dietary lutein also increased the
percentages of CD4+ and CD21+ lymphocytes on Week 12 but had no significant
effect on pan T, CD8 and MHC class II markers. Plasma IgG was higher (p<0.
05) in cats fed 10 mg lutein on Weeks 8 and 12. These results support the i
mmuno-modulatory action of lutein in domestic cats. (C) 2000 Published by E
lsevier Science B.V. All rights reserved.