Activation of macrophages by products of lymphocytes from normal and syphilitic rabbits

Abstract

The production of soluble macrophage-activating factors by lymphocytes from syphilitic and normal rabbits was examined. Culture supernatants of splenic lymphocytes cultured with Treponema pallidum antigens or concanavalin A were incubated with rabbit peritoneal macrophages in vitro. The macrophage monolayers were then washed and infected with log-phase Listeria monocytogenes. Activation of the macrophages by lymphocyte products was measured by the ability of the macrophages to resist intracellular multiplication of Listeria and thus survive infection. Macrophages incubated with supernatants of unstimulated lymphocytes or T. pallidum-stimulated lymphocytes from normal rabbits were unable to resist intracellular multiplication of Listeria. Specifically stimulated lymphocytes from syphilitic rabbits and mitogen-stimulated lymphocytes from both normal and syphilitic rabbits demonstrated a clear ability to produce soluble factors which conferred upon macrophages the ability to limit the intracellular growth of the bacteria. Antigen or mitogen alone was unable to activate the macrophages; the presence of lymphocyte products was required.

The Th1/Th2-like switch in syphilitic infection: is it detrimental?

“…There are relatively large numbers of T lymphocytes and macrophages. The bulk of immune clearance appears to occur, as suggested by Lukehart et al and Sell et al (23,25,43), via DTH stimulating enhanced macrophage activation. It is most important to emphasize, however, that "sterilizing immunity" does not develop, and rabbits remain infectious, harboring virulent organisms at the infection site as well as in the spleen, lymph nodes, and bone marrow (chronic disease).…”

Characterization of the serum requirement for macrophage-mediated killing of Treponema pallidum ssp. pallidum: Relationship to the development of opsonizing antibodies

“…Lastly, the possible enhancement of phagocytic and treponemicidal capacities by lymphokine activation of macrophages is relevant to the situation in vivo, where the influx of large numbers of T lymphocytes and macrophages precede bacterial clearance. Macrophage-activating factors are produced by sensitized T cells in response to stimulation with treponemal antigens [24], and in vivo activation of hamster macrophages by treatment with lipopolysaccharide or thioglycolate enhances clearance of T. pallidum ssp. pertenue infection [25].…”

Isolation and Laboratory Maintenance of Treponema pallidum

“…Saline/20% NRS: mix 10 ml saline (0.14 M NaCl; see recipe) and 1 to 2 ml normal rabbit serum (NRS; see recipe) Additional reagents and equipment for performing venipuncture, lumbar puncture, and punch biopsy (qualified personnel), anesthetizing rabbits (e.g., see http://depts.washington.edu/auts/rabbit handout 2007.pdf), inoculating rabbits and harvesting treponemes (Basic Protocol 1), and performing VDRL/RPR and FTA-ABS screening (Lukehart, 1982;Larson, 1999) 1c. To collect chancre exudate: Squeeze the chancre gently so that serous exudate accumulates in the ulcer; avoid blood contamination of the exudate.…”