Administration of DNP-BGG to newborn guinea pigs resulted, in more than half of the animals, in the specific suppression of delayed hypersensitivity to DNP-BGG and BGG, as shown after immunization with DNP-BGG in complete Freund's adjuvant. In contrast, all animals formed antibodies to DNP-BGG, whether or not delayed hypersensitivity to this antigen was present. No difference in antibody titers...

Arsanilic acid conjugated to poorly antigenic carriers was shown to be capable of producing good hapten-specific delayed hypersensitivity but poor haptenspecific antibody production (1). This hapten-specific delayed hypersensitivity was only transiently suppressed by intravenous injections of monovalent conjugates of arsanilic acid and N-acetyltyrosine (2). On the other hand , intramuscular, in...

Two homologous lightly coupled dinitrophenyl conjugates of poly-L-lysine of differing average molecular sizes were compared with regard to their abilities to elicit in guinea pigs specific delayed hypersensitivity skin reactions, passive cutaneous anaphylaxis, and active Arthus reactions. Equal concentrations by weight (but not equimolar concentrations) of the two conjugates elicited equally in...

A highly purified pneumococcal polysaccharide (Type II SSS) is a very efficient inducer of delayed hypersensitivity in random-bred guinea pigs. The cellular reactivity induced by this polysaccharide administered subcutaneously in complete Freund's adjuvant is of "tuberculin type"; it increases in intensity with time after the sensitizing injection, as judged by skin tests, the macrophage inhibi...

Two potential mechanisms for terminating delayed hypersensitivity (DH) reactions have been examined in desensitized guinea pigs. Lack of macrophage responsiveness to lymphokines was sought as an explanation for the reduced ability of these animals to express delayed hypersensitivity. Skin-reactive factor was injected into the skin of desensitized guinea pigs and a control group of similarly imm...

Labeled monocyte infiltration techniques have been used to study delayed-type hypersensitivity responses in mice immunized with St. Louis encephalitis virus. A delayed 24- to 48-h inflammatory response occurred 6 to 7 days after immunization. This response can be potentiated by cyclophosphamide treatment, by BCG administration, or by splenectomy. Treatments known to selectivity inhibit T-cell f...

INTRODUCTION Persistence of allergen and immunocompetent cells at sites of healed contact dermatitis has been reported. Flare-up reactions triggered by patch testing and after systemic provocation with allergen are well-known phenomena. To our knowledge, we report the first flare-up of a previous patch test site following casual cutaneous application of nickel in an individual with hitherto lat...

Experiments carried out with several well defined antigenic systems (hapten conjugates of poly-L-lysine and guinea pig serum albumin) in guinea pigs demonstrated that: 1. Arthus reactions also manifest carrier specificity, although to a smaller extent than do delayed hypersensitivity reactions. 2. Desensitization by injection of minute doses of antigen results in moderate specific desensitizati...