Fractionation of lymphocytes involved in the generation of cell-mediated cytotoxicity over insolubilized conjugated histamine columns

Spleen cells from normal BALB/c mice were cultured in vitro with irradiated C57BL/6 stimulating cells. Five days later the T cell-mediated cytotoxic activity of the effector cells was assessed with a 51Cr-release assay that used H-2bEL-4 tumor cells as targets. Before the BALB/c responding lymphocytes were sensitized they were fractionated by passing the spleen cells over insolubilized histamine rabbit serum albumin Sepharose columns (H-RSA-S) or over rabbit serum albumin Sepharose (RSA-S) control columns. Fractionation of cells over the H-RSA-S columns depleted or significantly reduced the cytotoxic potential of the unretained cells. All cytotoxic potential was recovered when the cells that adhered to the H-RSA-S were eluted from the columns. In contrast, no effect on responsiveness was detected after the cells had been fractionated over the control column. The loss of response potential by the cells that did not adhere to H-RSA-S could not be accounted for by removal of macrophages nor by the concentration of cells with suppressor activity in the effluent. These cell fractionation studies raise the possiblity but do not prove that cytotoxic precursor cells may express amine receptors that could be responsible for their retention by insolubilized histamine columns.

The effect of allogeneic presensitization on H-Y graft survival and in vitro cell-mediated responses to H-y antigen

C57BL/6 and C57BL/10 female mice were grafted with skin from male or female donors incompatible for H-2 and/or non-H-2 antigens. Syngeneic male grafts applied after the rejection of primary allografts or syngeneic male grafts were rejected in accelerated (second set) fashion, whereas male grafts applied after primary female grafts were not. In addition, C57BL/10 female spleen cells, primed in vivo with an allogeneic (BALB/c, CBA, or B10.BR) male graft and challenged in vitro in mixed lymphocyte culture with syngeneic (C57BL/10) male cells, produced cytotoxic cells specific for syngeneic male target cells. We conclude that at least some component of H-Y is detected by female responder cells on allogeneic male cells, and that the second set cell mediated response to H-Y is not necessarily restricted by the H-2 haplotype of the primary sensitizing strain. Moreover, (CBA X B10) F1 females, primed in vivo with male cells of one parental haplotype (B10 or CBA) and challenged in vitro with male cells of the other parental haplotype (CBA or B10), fail to lyse male target cells of either parental haplotype. It therefore seems unlikely that a helper determinant shared between B10 and CBA is sufficient to explain the ability of CBA male cells to prime H-2-restricted T-cell cytotoxic responses by B10 females.

Micromethods for induction and assay of mouse mixed lymphocyte reactions and cytotoxicity

A new method in which induction of mixed lymphocyte responses and cytotoxicity can be performed under identical conditions is described. This enables the investigation of the relationship between MLR and cytotoxicity. A micro method for the 51Cr release assay for cytotoxicity is described using both mitogen-induced blasts and tumors as target cells. Under the conditions used data obtained is suitable for linear regression analysis, enabling quantitative comparisons to be made.

Stimulation of mixed lymphocyte cultures and cytotoxic responses: evidence that T cells express SD but not LD antigens, whereas B cells express both

By separating T and B cells from stimulator spleens it has been found that mixed lymphocyte response (MLR) and cytotoxic cells are generated in responder T cell populations by B but not by T stimulator cells in a wide variety of strain combinations. It is suggested that MLR-stimulating or LD antigens are expressed on B but not T cells, and that their presence is necessary in order to generate cototoxic responses to H-2K and/or H-2D (or SD) antigens which are present on both T and B cells. The finding that B cells and macrophages stimulate MLR is consistent with the hypothesis that Ia antigens, expressed on both these cell types but not on nylon column purified peripheral T cells, are the MLR-stimulating or LD determinants.

The differentiation of cytotoxic T lymphocytes in vitro: an ultrastructural study

T killer cells were identified morphologically in two different culture systems. The first system allowed identification by comparing under identical culture conditions two types of stimulation, one leading to cytotoxic activity levels that were very high (H-2 stimulation) and the other to levels which were practically nil (M-locus stimulation). A second system allowed identification by the use of a collaborative system in which relatively pure precursors of T killer cells were mixed with precursors of T amplifier cells from which they were distinguishable by their Thy-l antigen. In this latter case, surface labelling techniques had to be used. As in the in vivo situation, T killer cells were medium-sized pale cells with evidence of a well-developed secretory and motile apparatus. No evidence of highly active protein synthesis was found. Other T cells were dark and mainly derived from the T amplifier population, again consistent with in vivo findings. There was considerable background proliferation, even in the absence of any added antigen, and this included the formation of some well-developed plasma cells.

Immunological reactivity of B mice reconstituted with various numbers of syngeneic bone marrow cells

Adult thymectomized mice were sublethally irradiated and reconstituted with various doses of syngeneic bone marrow. Immunological reactivity was assessed by allogeneic skin grafting at various intervals after reconstitution. It was found that reconstitution with high doses (1 X 10(7), 2 X 10(7)) of bone marrow was associated with an ability to reject allogeneic skin grafts and that this reactivity increased with time. Following rejection of a first skin graft, second grafts were rejected in an accelerated manner. These mice had measurable levels of Thy 1.2 positive cells in the spleen. In contrast, low-dose bone marrow reconstitution (1 X 10(6), 2 X10(6)) produced mice which did not reject either first or second allogeneic skin grafts, and such mice had at most only very low levels of Thy 1.2 positive cells in their spleens.

In vitro cell-mediated immune responses to the male specific(H-Y) antigen in mice

C57BL/10 female mice were primed to the male specific antigen H-Y, either by grafting with syngeneic male tail skin or by i.p. injection of syngeneic male spleen cells. Primed female spleen cells, either unseparated or filtered through nylon wool to remove most of the B lymphocytes, were then cultured for 5 days in vitro with irradiated syngeneic male spleen cells and assayed against 51Cr-labeled target cells. Both unseparated and nylon wool filtered female cells displayed significant cytotoxic activity restricted to male target cells. Pretreatment of sensitized female cells with antitheta serum and complement just before assay abolished cytotoxic responses. We were unable to demonstrate cell-mediated cytotoxic responses into two nonresponding strains, CBA and B10.A, which fail to reject male isografts. The cytotoxic activity of C57BL/10 female cells was restricted to male target cells histocompatible with C57BL/10 over at least a portion of the major (H-2) histocompatibility complex. We conclude that secondary in vitro cytotoxic responses against the H-Y antigen are mediated by cytotoxic T lymphocytes, and that the H-Y target cell antigen may be specified by the H-2 complex.

Regulation of the immune response by subclasses of T lymphocytes. I. Interactions between pre-killer T cells and regulatory T cells obtained from peripheral lymphoid tissues of mice

The generation of killer cells to alloantigens in vitro depends upon an interaction between two subclasses of peripheral T cells: "pre-killer" T cells and "regulatory" T cells. The pre-killer T cell, found in highest concentrations in peripheral lymph nodes of mice, is sensitive in vivo to the administration of small doses of anti-thymocyte serum (ATS) and is depleted in vitro by treatment with (a) anti-Thy-1.2 + C, (b) low doses (600 r) of x-irradiation. Specificity of pre-killer cells is supported by adsorption of pre-killer activity on appropriate allogeneic monolayers and by the specific absence of this activity from lymphoid tissues of mice rendered tolerant in neonatal life. Although T cells remaining in the spleen 2 days after a small dose of ATS (SPA-T) did not generate killer cells, this subset exerted substantial regulatory effects upon the generation of killer activity by pre-killer T cells. The addition of this population of regulatory T cells to small numbers of lymph node T cells (LN-T) resulted in substantial enhancement in the generation of killer cells from the LN-T pre-killers. The addition of SPA-T to larger numbers of LN-T (which produce strong responses alone), failed to enhance the response, and in some cases resulted in significant suppression which could not easily be accounted for by alteration in cell numbers in culture. Although amplifier activity was relatively radioresistant, "suppressor" activity was sensitive to relatively small doses of irradiation. The significance of this T-T interaction is discussed.

Regulation of the immune response by subclasses of T lymphocytes. II. The effect of adult thymectomy upon humoral and cellular responses in mice

The immunologic consequences resulting from thymectomy in adult life were investigated. Primary humoral responses were not diminished shortly after adult thymectomy, as judged by responses of intact thymectomized mice as well as by the ability of spleen cells from such mice to transfer primary responses. However, secondary humoral responses were substantially reduced in irradiated recipients of spleen cells from primed adult-thymectomized mice, suggesting that the thymus is required in adult life to maintain a population of cells important in the generation of immunologic helper memory. By contrast, small doses of anti-thymocyte serum, which primarily affect recirulating T cells, abrogated the primary humoral response, but allowed the subsequent development of immune memory. Using a technique permitting in vitro sensitization of purified T cells to alloantigens, it was shown that adult thymectomy increases the ability of T cells to generate primary cytotoxic responses, but had little effect upon the development of cytotoxic T memory activity. These experiments suggest that in adult life the thymus maintains a regulatory population of T cells in peripheral tissues which suppress early T cell differentiation to cytotoxic effector cells and potentiates the development of immune memory.

Why Measure Blood Barbiturates?

Phenobarbitone levels in the blood do not always provide a reliable guide in the management of the poisoned patient. They may rise in response to active treatment though the patient may be improving clinically. Some reasons for this are considered, with illustrations from three cases. It is concluded that the poor correlation of phenobarbitone levels with a patient's condition is due not to inadequate analytical techniques but to the poor representation of the “whole body” situation by a single blood specimen. The usefulness of analysing such specimens is questioned.

Immunological disease induced by injecting F1 lymphoid cells into certain parental strains

Injection of neonatal Balb/c or C57Bl/6 mice with C57Bl/6 x Balb/c)F1 lymphoid cells leads to transient chimerism and runting, and to splenomegaly, deficient T-cell function and a gradual replacement of lymphoid organs with abnormal reticular cells. Activated MuLV can be isolated from such mice. It is proposed that either graft-versus-host or host-versus-graft allogeneic reactivity activates endogenous MuLV virus, which then causes functional and morphological abnormalities in the lymphoid organs.

An evaluation of a drug administration system in a psychiatric hospital

Previous studies have shown that in-patients in psychiatric hospitals may not always take prescribed drugs reliably (Hare and Wilcox, 1967; Wilson and Enoch, 1967; Irwinet al., 1971).

The histological response to a xenogeneic tumour in mice

We have examined, by conventional histological methods, the immune response of normal and ALS-treated mice to a tumour xenograft. In normal mice the histology of the tumour site and lymphoid organs is in agreement with the hypothesis that rejection of tumour is by a cell-mediated response. In ALS-treated mice, lymphoid organs severely depleted of small lymphocytes, show many blast cells which may be responsible for in vitro cytotoxicity. After cessation of ALS there is still a striking lack of infiltrate at the tumour site suggestive of some form of `blocking' mechanism.

Screening for Paracetamol Poisoning

The commonly used tests for the detection of paracetamol or its metabolites in cases of self-poisoning are either non-specific or time consuming. The need for screening all cases of self-poisoning for paracetamol ingestion is emphasised and a test is recommended which combines the advantages of increased specificity with those of a short procedure.

Prolonged administration of antithymocyte serum in mice. II. Histopathological investigation

Prolonged administration of ATS to mice resulted in depletion of small lymphocytes in the thymus-dependent (paracortical) areas of lymph nodes in all mice. Small lymphocyte depletion of the thymus-dependent periarteriolar region of the spleen was present in most mice, although this feature was masked by plasmacytosis in this region in some. Depletion of small lymphocytes in the thymus-dependent areas of Peyer's patches was evident in some of the younger mice. None of these changes in lymphoid organs were seen in control mice, untreated or given NRS. The thymus was unaffected except in some ATS- or NRS-treated mice which were sick and/or old, in which the narrowing of the thymic cortex was attributed to non-specific stress. Plasmacytosis was seen in the medullae of lymph nodes of both ATS- and NRS-treated mice, although it was more intense in the latter. In non-lymphoid organs the most striking changes were seen in the kidneys of mice treated both with ATS and NRS. Complex-type nephritis followed by amyloidosis was seen in a large proportion of mice over 6 months old in both these groups and in these mice amyloid was seen frequently in other organs, including spleen and liver. Tumours occurred in fifty-four ATS-treated mice, but in no other group. Fifty-two of these tumours were attributable to polyoma virus; two other were lymphoblastomas. Reticulum cell hyperplasia was seen in two further mice.

The erythrocyte glutathione reductase activity (E.C. 1.6.4.2) of healthy blood donors

The erythrocyte glutathione reductase activity was measured in 199 healthy blood donors. The normal range was found to be 6.3 to 39.0 IU/10(9) erythrocytes. There was no variation related to either age or sex.

Ocular myasthenia: evaluation of Tensilon tonography and electronystagmography as diagnostic tests

The value of electronystagmography (ENG) and of tonography in monitoring the beneficial effect of edrophonium chloride (Tensilon) on the extraocular muscles in myasthenia gravis has been assessed. Studies were performed on 17 patients with myasthenia gravis and on 18 control subjects, of whom nine had extraocular muscle weakness due to myopathic or neurogenic lesions.Electronystagmography recorded the repetitive following movements of the eyes elicited during optokinetic nystagmus. Neuromuscular fatigue with the subsequent beneficial response to Tensilon was clearly seen in 50% of patients with myasthenia. False positive responses were not seen in control subjects but in many of these, as in the remaining myasthenic patients, the amplitude and rate of nystagmus seen in the ENG was very variable. These difficulties suggest that the ENG is of limited value as a diagnostic test in myasthenia gravis.Tonography, recording the intraocular pressure of the eye continuously over four minutes, was found to be of considerable value. We found that the intraocular pressure fell on average by 1·6 to 1·8 mm Hg over a one minute period in the control recordings but increased by a mean of 1·6 mm Hg in patients with myasthenia, with a peak effect 35 seconds after Tensilon. In only one patient was there a complete failure of response. This patient, and also another woman who showed a less striking response, had severe myasthenia with a fixed ocular weakness. It is suggested that an absence of any increase in tension with Tensilon may be seen in patients with permanent neostigmine-resistant myopathic change. A small false positive response was seen on one occasion only in a patient with a sympathetic nerve lesion.Tensilon tonography, as a simple painless procedure, would appear to be of considerable value in the diagnosis of ocular myasthenia and also as a diagnostic test in the exclusion of myasthenia as a cause of isolated extraocular neuromuscular weakness.