Thymus independent antigen

Hoffman et al.52, presented evidence that a single oral dose of tilorone enhanced the primary immune response to sheep red blood cells (SRBC) in mice as measured by the Jerne Plaque technique. They also reported an increase in hemolysin titer after tilorone administration. To further evaluate the action of tilorone on humoral antibody responses, Megel ef a/.3 have studied its effect on 19S and 7S production in the primary and secondary immune responses in mice. It was found that tilorone elevated 19S antibody titer on days 3 and 4 after immunization. After 9 days of continuous drug administration, the 19 S response for both groups was diminished compared to days 3 and 4 however tilorone was found to cause a significant increase in the 7S antibody production compared to controls. Tilorone also stimulated the 19S response to E. coli endotoxin, a thymus-independent antigen, on days 3 and 4 after immunization. 

The linear molecules of PVP resemble those of other repetitive polymers like dex-trans, mannans, levans, etc. As antigens, many of such polymers are thymus-independent antigens. It was shown by Gill and Kunz (1968) that PVP consistently elicited a moderate amount of antibody upon immunization of rabbits, using doses between 10 and 100 ig. In mice, PVP has been shown to produce a thymus-independent humoral antibody response (Andersson 1969 Andersson and Blomgren 1971). It is probable that the antigenic determinants comprise sequences on the molecular chain consisting of 3-6 vinylpyrrolidone residues. 

Moller, G., Michael, G. Frequency of antigen sensitive cells to thymus independent antigens. Cell. Immunol. 2, 309-316 (1971). 

MILLER NW, CLEM Lw (1984), Temperature-mediated processes in teleost immunity differential effects of temperature on catfish in vitro antibody responses to thymus-dependent and thymus-independent antigens , / Immunol, 133,2356-9. 

Nitschke, L., Kosco, M.H., Kohler, G., Lamers, M.C. (1993). Immunoglobulin D-deficient mice can mount normal immune responses to thymus-independent and -dependent antigens. Proc. Natl. Acad. Sci. USA 90, 1887-1891. 

Amlot PL, Grennan D, Humphrey JH. Splenic dependence of the antibody response to thymus-independent (TI-2) antigens. Eur J Immunol 1985 15 508-512. 

Immunologically reactive or immunocompetent cells are lymphocytes which, together with granulocytes and erythrocytes, originate from common hemopoietic stem cells (Wu et al. 1967). The sites of primary lymphopoiesis are the bursa of Fabricius (in birds) and the thymus in mammals no bursa has been found but an equivalent organ is inferred (Mitchell and Miller 1968 Perey et al. 1968 Owen and Ritter 1969). Lymphocytes which differentiate within the thymus independent of antigenic influence become thymus-derived or thymus-processed lymphocytes, so-called T-cells. It is now generally accepted that a cooperation between T-cells and bursa-equivalent lymphocytes (B-cells) is necessary for induction of IgM... 

One of a series of arylhydroxytriazenes, PR-H-986 BS (JL) was effective in both hvimoral and cell-mediated immune responses and in rat adjuvant-induced arthritis.97 The orally active antiviral agent tilerone (2), effectively inhibited symptoms of adjuvant arthritis and allergic encephalomyelitis in rats but paradoxically, it potentiated the humoral immune response to the thymus dependent and Independent antigens as well as to homocytotropic antibody.98... 

For most antigens, the production of antibody (immunoglobulin) is based on the cooperative interaction of two types of lymphocyte, called T-cells (thymus-derived) and B-cells (bone marrow-derived). The T-cells, preprimed with macrophage-presented antigen, stimulate the B-cells to secrete copious quantities of antibody. However, on the basis of animal studies, such polysaccharide antigens as the type III pneumococcal polysaccharide have been considered to be T-cell-independent, as they are capable of triggering B-cells to produce antibody (IgM) in T-cell-deficient mice.167 These studies also indicated... 

Modifications of L-selectin expression were studied on T cells, immediately after their exit from the thymus of fetal and newborn animals [66]. It was observed that the percentage of L-selectin-expressing thymocytes exported per day decreased by half after birth, with a remarkable heterogeneity of L-selectin expression (number of cells and intensity of expression) on exported and mature T cells. Furthermore, emigrant immature T cells weakly express L-selectin and during maturation L-selectin is up-regulated independently of extrinsic antigen. 

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