AGE-ASSOCIATED INVOLUTION OF CELLULAR IMMUNE FUNCTION .1. ACCELERATED DECLINE OF MITOGEN REACTIVITY OF SPLEEN-CELLS IN ADULT THYMECTOMIZED MICE

  • 1 January 1976
    • journal article
    • research article
    • Vol. 116  (4) , 982-988
Abstract
Autoimmune-susceptible (A/J and C57BL/6J) and non-autoimmune-susceptible (DBA/1J) strains of mice were adult thymectomized (aTx). Groups of mice, treated by aTx, aTx and 330 rads (R), aTx and 650 R, and 330 R or 650 R only, were compared to normal age-matched control (normal and sham Tx) mice. T [thymus-derived] cell functions were then followed as measured by in vitro spleen cell responsiveness to the T cell mitogens phytohemagglutinin (PHA) and staphylococcal enterotoxin B (SEB) in a long-term study. A decline in spleen cell responsiveness with natural aging up to 18 mo. of age was seen to PHA in all 3 strains and to SEB in A/J and C57BL/6J mice. Adult Tx alone was followed by an accelerated decline in spleen cell responsiveness to PHA and SEB in all 3 strains of mice. Irradiation combined with aTx-reduced spleen cell responsiveness to SEB in A/J and DBA/1J mice. Irradiation with or without aTx diminished the bone marrow stem cell pool, as measured by exogenous colony-forming units, and the hematocrit of all 3 strains of mice. The natural decline in cellular immunity with aging was accelerated by aTx in autoimmune-susceptible and non-autoimmune-susceptible strains of mice. Physiologic thymic function(s) must continue throughout life to maintain T cell function.