Oral tolerance is a physiological immune mechanism, which controls the outcome of deleterious hypersensitivity reactions to environmental antigens absorbed through the gastrointestinal tract, and maintains homeostasis. Using a mouse model of oral tolerance of delayed type hypersensitivity to contact allergens, i.e. haptens, we have examined the mechanisms involved in the induction of oral toler...

The expression of delayed-type hypersensitivity in animals has been inhibited by a variety of anticoagulants, but direct evidence for activation of clotting in the evolution of these reactions has been lacking. Using the fluorescent antibody technique we here demonstrate that fibrin deposition is a prominent and consistent feature of both allergic contact dermatitis and classic delayed hypersen...

Contact hypersensitivity (CHS) mouse model induced by 2, 4-dinitrofluorobenzene (DNFB) is thought to be a T helper 1 (Th1)-dominant response and used for investigating anti-inflammatory and immunosuppressive agents. However, it is hardly used for screening large-scale drugs because of the large number of animals and complex mechanisms involved in-vivo. In this study, we focused on whether T lym...

Mice vaccinated with mycobacterial ribonucleic acid (RNA) produced a high immune response and did not develop delayed hypersensitivity to purified protein derivative (PPD), and rifampin had no effect on the immune response. Mice vaccinated with viable H37Ra cells produced a high immune response and did develop delayed hypersensitivity to PPD. Rifampin had no effect on this immune response, but ...

Delayed onset erythematous skin reactions elicited in guinea pigs early in the course of sensitization with azobenzenearsonate-protein conjugates or with protein antigens in incomplete Freund's adjuvant or in saline were found to have a characteristic morphology which sets them apart from delayed hypersensitivity and the classic antibody mediated reactions. The principle feature was massive der...

Hypersensitivity responses to two highly purified and well characterized mycobacterial proteins and a preparation of mycobacterial arabinogalactanarabinomannan were studied by using guinea pig skin tests and in vitro-cultured human lymphocyte mitogenesis stimulation assays. The purified proteins were found to elicit delayed-type hypersensitivity skin test reactions and to stimulate mitogenesis ...

The staphylococcidal capability of populations of peritoneal macrophages in rabbits has been measured before and after repeated infections with Staphylococcus aureus. Such rabbits after infection showed delayed-type hypersensitivity to S. aureus antigens, but the staphylococcidal capability of the peritoneal macrophages was not increased. This result at the cellular level is in agreement with p...

1. In guinea pigs, aminomethylpteroylglutamic acid (methotrexate) is capable of blocking the development of delayed skin hypersensitivity, the primary antibody response, and the specific febrile response to ovalbumin and diphtheria toxoid. The primary antibody response is more easily inhibited than is the development of delayed skin hypersensitivity. 2. The effect of methotrexate on immunologic...

Ulcerative dermatitis (UD) is common in captive sea turtles and manifests as skin erosions and ulcers associated with gram-negative bacteria. This study compared clinically healthy and UD-affected captive turtles by evaluating hematology, histopathology, immunoglobulin levels, and delayed-type hypersensitivity assay. Turtles with UD had significantly lower weight, reduced delayed-type hypersens...