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At least 55 records · Page 3Linked to original sources

Whole-body hyperthermia maintains the secondary immune response of specific antitumour immune T cells.

The effect of hyperthermia on the spleen cells of Meth A-hyperimmunized BALB/c mice (Meth A-Im-SPL) was examined. Three kinds of heating were employed: (a) a cell suspension of Meth A-Im-SPL was directly heated for 1 h at 41 degrees C; (b) the whole body of Meth A-hyperimmunized mice was heated in the same manner--the antitumour activity of Meth A-Im-SPL was examined by Winn assay after heating; (c) the whole body of BALB/c mice intradermally inoculated with a mixture of Meth A-Im-SPL and Meth A cells (Winn assay) was heated in the same manner. The results showed that the antitumour activity of Meth A-Im-SPL was not affected by heating in vivo (Experiments B and C), although it was affected in vitro (Experiment A). Furthermore, slight augmentation of the antitumour activity of Meth A-Im-SPL was observed on heating in vivo. This shows the possibility of combination therapy involving adoptive transfer and whole-body hyperthermia.

Animals↗

Accumulation of CD8+ T cells in advanced-stage tumors and delay of disease progression following secondary immunization against an immunorecessive epitope.

Self-reactive T cells that survive the process of positive and negative selection during thymocyte development represent potential effector cells against tumors that express these same self-Ags. We have previously shown that CD8+ T lymphocytes (T(CD8)) specific for an immunorecessive epitope, designated epitope V, from the SV40 large T Ag (Tag) escape thymic deletion in line SV11 Tag-transgenic mice. In contrast, these mice are tolerant to the three most dominant Tag epitopes. The majority of the residual epitope V-specific T(CD8) have a low avidity for the target epitope, but a prime/boost regimen can expand higher avidity clones in vivo. Whether higher avidity T(CD8) targeting this epitope are affected by Tag-expressing tumors in the periphery or can be recruited for control of tumor progression remains unknown. In the current study, we determined the fate of naive TCR-transgenic T(CD8) specific for Tag epitope V (TCR-V cells) following transfer into SV11 mice bearing advanced-stage choroid plexus tumors. The results indicate that TCR-V cells are rapidly triggered by the endogenous Tag and acquire effector function, but fail to accumulate within the tumors. Primary immunization enhanced TCR-V cell frequency in the periphery and promoted entry into the brain, but a subsequent booster immunization caused a dramatic accumulation of TCR-V T cells within the tumors and inhibited tumor progression. These results indicate that epitope V provides a target for CD8+ T cells against spontaneous tumors in vivo, and suggests that epitopes with similar properties can be harnessed for tumor immunotherapy.

Adoptive Transfer↗

[Effect of B-activin on the rosette-forming capacity of mouse lymphocytes at the peak of a secondary immune response to ram erythrocytes].

The effect of B-activin secreted by bone-marrow cells in response to the expression of antigen-recognizing receptors at the peak of immune response to SRBC was studied. A negative correlation between the number of immune RFC and antibody-producing cells under the influence of B-activin was established. It was shown that the decrease in the number of immune RFC was the result of precommitted B-lymphocyte maturation into plasmatic cells.

Activins↗

Delayed secondary immune response in mice immunized with Toxoplasma antigens and its effect for protection against Toxoplasma gondii.

Primary immune response by mice immunized with Toxoplasma peritoneal exudate (PE) was produced slowly at a low level. To induce high Toxoplasma antibodies, mice should be boostered after the primary immune response reached the peak in 4 weeks or later. Immunization of mice with PE alone in 4 weeks could suppress the growth of Toxoplasma but could not accomplish protection. Two of 9 mice immunized with PE in complete Freund's adjuvant (CFA), and 16 of 27 mice immunized with PE containing Toxoplasma ( ToxoPE ) in CFA were protected against a challenge of 1 X 10(3) Toxoplasma, RH strain. The mice surviving to the challenge showed complete protection against a rechallenge of higher dose, 1 X 10(6) RH strain. Their ascites were very high in LA titer and would be a great source for obtaining high titer antibodies to Toxoplasma without contamination of host serum components. Biological characters of Toxoplasma, RH strain, in chronic infection of mice are discussed.

Animals↗