Primary and secondary delayed-type hypersensitivity to minor histocompatibility antigens in the mouse

Delayed type hypersensitivity responses to the Qa-Tla region of the mouse major histocompatibility complex

We have elicited a small but significant delayed-type hypersensitivity response against the Qa-Tla region of H-2 following immunisation of C57BL/6 mice with cells from the congenic strain C57BL/6.Tlaa. Optimal responses were detected 14 days after immunisation with 10-40 X 10(6) cells. The significance of delayed type hypersensitivity to Qa-Tla is discussed in relation to the genetic loci which map to this region.

Secondary delayed type hypersensitivity to H-2 subregion-coded alloantigens

Secondary type delayed type hypersensitivity (DTH) in mice against class I alloantigens or non-H-2 alloantigens is characterized by an earlier appearance of DTH reactivity after booster immunization compared with the development of DTH reactivity after primary immunization. In contrast to the primary and secondary DTH against class I or non-H-2 alloantigens, the development of secondary DTH against class II alloantigens or a set of alloantigens that includes class II alloantigens is not faster than the development of primary DTH. Thus, primary and secondary immunization with class II alloantigens prevents secondary type DTH reactivity to simultaneously administered class I alloantigens and non-H-2 alloantigens.

Differential influence of 2'-deoxyguanosine on the induction and expression of suppressor T lymphocytes in vivo

Subcutaneous (sc) immunization of mice with allogeneic spleen cells can induce delayed-type hypersensitivity (DTH) to histocompatibility antigens. Intravenous immunization with irradiated allogeneic spleen cells, on the other hand, induces suppressor T (Ts) lymphocytes. These Ts cells are capable of suppressing the host-versus-graft (HvG) DTH reactivity which normally arises after sc immunization. Moreover they can suppress the development of antihost DTH effector T cells during graft-versus-host (GvH) reactions. These models for HvG and GvH DTH reactivity were used to study the influence of 2'-deoxyguanosine (dGuo) on the induction, further development, and expression of Ts cells in vivo. It was found that administration of dGuo inhibits the proliferation-dependent induction and further development of Ts cells, but not the suppression mediated by already activated Ts cells.

The in vitro induction of delayed-type hypersensitivity to allo-antigens of the mouse

An in vitro procedure has been developed which allows the induction of delayed-type hypersensitivity (DTH) to major allo-antigens of the mouse. Murine spleen cells cultured with irradiated allogeneic cells develop allo-specific DTH reactivity (DTHR). The variables assessed to provide optimal induction of DTHR were (i) the culture system, (ii) the density of responders and the number of stimulator cells and (iii) the kinetics of induction. The reactivity of the allo-specific cells was assayed in 3 different ways in order to select the most sensitive: (i) by local footpad transfer into a mouse syngeneic with the responder cells together with the eliciting (irradiated) antigen-bearing cells; (ii) by local transfer into the footpad of a mouse syngeneic with the stimulator cells, in which the allo-antigens present in the subcutaneous tissues elicit the response, and (iii) by intravenous transfer into syngeneic or allogeneic mice which are challenged 24 h later in the footpad with spleen cells bearing the haplotype of the stimulator. The second assay is clearly the most sensitive (2X that of the first and greater than 20X that of the last). Observations are reported demonstrating the specificity of the swelling reaction. The kinetics of swelling and its T-cell dependence provide strong grounds for believing that the reaction is due to classical delayed-type hypersensitivity. Furthermore the T cells mediating the swelling are of the phenotype Lyt1+ Lyt2(+/-) and Ia- and are radiation resistant, whereas the ability to produce a swelling reaction is sensitive to 1000 rads. whole body irradiation. The system has been applied to determine both the specificity of T cells mediating DTH to major and minor allo-antigens and whether cytotoxic T cells (CTL) and DTH-active T cells are always induced under the same conditions.

Secondary delayed-type hypersensitivity to sheep red blood cells and minor histocompatibility antigens in mice: transfer of memory by recirculating thoracic duct lymphocytes

Secondary delayed-type hypersensitivity (DTH) in mice to sheep red blood cells (SRBC) and minor histocompatibility (H) antigens is dependent on long-lived memory T cells. In this paper we investigated whether these memory T cells recirculate. It was shown that late phase "immune' thoracic duct lymphocytes (TDL) from mice which were immunized with SRBC or non-H-2-incompatible spleen cells several weeks previously could adoptively transfer secondary DTH to these antigens. Passing the immune TDL through intermediate recipients demonstrated that these SRBC- or minor H-antigen-reactive memory T cells recirculate from blood to lymph. In contrast to mice immunized with minor H antigens, no secondary type DTH reactivity could be demonstrated in mice immunized with H-2-incompatible spleen cells. Also, after adoptive transfer of TDL from mice immunized with H-2-alloantigens, it was impossible to demonstrate an accelerated DTH reactivity.

Regulatory mechanism of delayed-type hypersensitivity in mice. IV. Effect of suppressor T cells on the development of memory T cells involved in accelerated generation of DTH-effector cells in vitro

The effect of suppressor T cells (Ts) on the induction and the subsequent development of memory T cells for delayed-type hypersensitivity (DTH) was examined. The memory cells were induced in the spleens of mice primed previously with a low dose of reduced and alkylated ovalbumin (Ra-OA), and they generated DTH-effector T cells (DTH-Te) in a significantly accelerated fashion when cultured with OA in vitro. Ts were obtained from the spleens of mice which received OA-coupled spleen cells i.v. 4 days previously, and they inhibited antigen-specifically the induction of DTH responses in the recipient mice sensitized with alum-absorbed OA only when transferred with 5 weeks before sensitization. The spleen cells from mice given Ts together with the priming antigen 7 weeks before culture failed to generate DTH-Te in an accelerated manner on restimulation with OA in vitro. The memory cells from primed mice also did not cause accelerated generation of DTH-Te, when cultured with Ts in the presence of OA in vitro. These results indicate that both the induction of the memory cells by priming with antigen in vivo and the subsequent development of memory cells to DTH-Te by restimulation in vitro are inhibited independently by Ts. This corresponded well with the effect of Ts on the development of DTH-memory in vivo.

Regulatory mechanism of delayed-type hypersensitivity in mice. III. In vitro analysis of memory T cells involved in augmentation of DTH responses

The memory of delayed-type hypersensitivity (DTH), manifested by the augmented responsiveness upon challenge with alum-absorbed ovalbumin (OA), was induced in mice primed 7 days, 21 days, or 90 days previously with 1 microgram of reduced and alkylated OA. The memory cells involved in the augmentation of DTH responses were analyzed in the in vitro induction system of T cells which mediate DTH against OA. Spleen cells from the primed mice generated DTH-effector T cells (DTH-Te) in a significantly accelerated fashion, compared with unprimed spleen cells, when cultured with OA. The accelerated generation of DTH-Te in vitro was induced antigen specifically and was dependent on a certain T cell population in the primed spleen. The T cell population was found in the spleen of primed mice for at least 3 months after priming, corresponding to the persistence of DTH-memory in vivo. Moreover, it was fractionated in the high-density layer by discontinuous bovine serum albumin gradient centrifugation. The high-density cell population decreased in density with increase in the time of culture and developed into DTH-Te, which were separated in the low-density layer on day 4 of culture. These results indicate that the T cells involved in the accelerated generation of DTH-Te in vitro are long-lived DTH-memory T cells, which are probably precursor cells, capable of differentiating into DTH-Te upon challenge with the antigen.