J.R. Frey

Studies on Contact Hypersensitivity to Chromium in the Guinea Pig

Macrophage migration inhibition and migration inhibitory factor (MIF) production were investigated in guinea pigs sensitized to potassium dichromate. The migration of peritoneal exudate cells from hyp

Development of contact sensitivity to DNFB in guinea pigs genetically differing in their response to DNP skin protein conjugates.

Strain 13 guinea pigs sensitized either with dinitrofluorobenzene (DNFB) or with a homologous DNP skin protein conjugate (DNP-GPSP) responded equally well to both an epicutaneous test with the hapten

Induction and Termination of Immunological Unresponsiveness to DNCB in Guinea Pigs

Tolerance and desensitization to DNCB are based on different mechanisms. Temporary desensitization of DNCB-contact sensitive guinea pigs may be caused by a direct inactivation of specific effector cells by the intravenously injected hapten whereas in tolerance to DNCB induced by pretreatment of normal animals with DNBSO3, suppressor cell activity may account for specific unresponsiveness.

The Induction of Immunological Tolerance During the Primary Response

By injecting adult guinea pigs intravenously with dinitrochlo-robenzene sulfonate (DNBSO3) 2 to 24 h after applying a sensitizing epicutaneous dose of dinitrochlorobenzene (DNCB), the production of PCA-detectable anti-DNP antibodies and the induction of contact hypersensitivity to DNCB is strongly depressed for over 14 weeks. The proportion of animals acquiring this state of specific unresponsiveness as well as its stability against a second sensitizing attempt with DNCB alone are clearly dependent on the dose of DNBSO3 injected and on the time interval elapsing between both hapten applications. However, the tolerogenic effect of DNBSO3 is stronger when injected some weeks before sensitization. The results obtained are discussed on the basis of current concepts on the relationship between antigen and immunocompetent cells. The possibilities to interpret our findings by means of reversible blocking or affinity labelling of cellular receptors, specific annihilation of antigen-sensitive cells or immune deviation are considered.

The Immunogenicity of Phenacetin and some of its Metabolites in Guinea Pigs

Guinea pigs were sensitized by p-phenetidin and 2-hydroxy p-phenetidin, two minor metabolites of phenacetin, as demonstrated by delayed type skin tests in vivo and by specific stimulation of sensitized leukocytes in vitro, phenacetin itself and the major metabolite N-acetyl-p-aminophenol being inactive. On the other hand, p-phenetidin as well as phenacetin itself induce immunological tolerance and desensitization of already sensitized animals. In this system, however, exclusively the oral route appears to be effective for induction of immunological tolerance and desensitization, in contrast to the intravenous route which is effective in other haptenic systems.

Induction of Tolerance During the Primary Response to Simple Chemicals

The contact hypersensitivity and the production of antidinitro-phenyl antibodies induced in guinea pigs by epicutaneous application of dinitrochlorobenzene (DNCB) can be inhibited when dinitro-benzolsulfonate is injected i.v. during the primary response, i.e. 6 to 24 h after the topical application of DNCB. The tolerance so obtained is specific and remains for 2 to 3 months, but can be broken in some of the animals by a renewed contact with DNCB.