Perforin expression in human cell-mediated luteolysis

After ovulation and in the absence of fertilization, the human corpus luteum regresses in an orderly sequence of morphological changes. This study demonstrated that luteal regression involved progressive infiltration of lymphocytes and macrophages. The inflammatory infiltrate began in the theca externa and gradually invaded granulosa cells, with maximum accumulation of lymphocytes and macrophages at the time of menstruation. Immunoperoxidase staining showed that the majority of lymphocytes were CD2+, CD3+, CD8+ T lymphocytes, and 15% of these T cells expressed perforin, a cytolytic protein implicated as a mediator of cytotoxicity. The remaining mononuclear infiltrate showed strong reactivity with monocyte/macrophage markers. These findings indicate that (a) a physiologic cell-mediated inflammatory process in the regressing human corpus luteum is mediated mainly by CD8+ T lymphocytes and cells of monocyte/macrophage lineage and (b) perforin expression in T lymphocytes supports a possible role for cytolytic T cells during the physiologic inflammatory response in human luteolysis.

Perforin expression in endometrium during the menstrual cycle

Perforin is a marker of functionally active cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells. We examined perforin expression in endometrium throughout the menstrual cycle. In addition, perforin expression was studied in endometrial leukocytes in women with anovulatory cycles with or without progesterone therapy and in postmenopausal women. In the endometrium, perforin-positive endometrial lymphocytes increased in numbers in the middle through late secretory phases. In women with anovulatory cycles, the proliferative endometrium, before estrogen withdrawal endometrial breakdown, contained less perforin-positive lymphocytes compared with the premenstrual endometrium of the normal menstrual cycle. The progestin-induced endometrial decidualization was accompanied by an extensive recruitment of perforin-positive cells. In contrast, the postmenopausal atrophic endometrium showed complete absence of perforin-positive cells. The lymphocytes isolated from secretory endometrium were CD3-, CD56+ (approximately 80%) or CD3+, CD8+ T-cell receptor (TCR)-gamma delta- (approximately 20%). Almost 90% +/- 5.5 of the CD3-, CD56+, and up to 25% +/- 7% of CD8+ T lymphocytes contained perforin. Perforin expression was further confirmed in endometrial lymphocytes by Northern blot analysis. In vitro, isolated endometrial lymphocytes exhibited NK-like cytotoxicity. After cyclic hormone withdrawal during normal menstrual cycle, these perforin-positive cytotoxic cells may be involved in endometrial stromal breakdown during menstruation.

Antibodies to the extractable nuclear antigens (ENA) in Pakistani patients with systemic rheumatic disease

Autoantibodies to the saline extracts of cells are being used as diagnostic and prognostic markers in the investigation of patients with suspected systemic rheumatic disease. These are also called antibodies to the extractable nuclear antigens or anti ENA antibodies. We used saline extracts of human spleen cells and rabbit thymus extract to detect six subtypes of anti ENA antibodies, namely anti SSA (anti Sjogren's syndrome A), anti SSB (anti Sjogren's syndrome B), anti RNP (anti Ribonucleoprotein), anti Sm (anti Smith), anti Jo-1 (anti Jo-1) and anti Scl 70 (anti Systemic sclerosis 70) antibodies. Two hundred and thirty-seven patients' sera were screened in the department of Immunology, Armed Forces Institute of Pathology (AFIP), Rawalpindi, over a period of 16 months. Fifty-seven were positive for auto antibodies, of which 26 had anti SSA antibodies, 12 anti SSA+ anti RNP+ anti Sm antibodies, 7 anti RNP+ anti Sm antibodies, 6 anti SSA+ anti SSB antibodies, 5 anti SSA+ anti RNP antibodies while one patient showed only anti RNP antibody. The detection of the anti ENA antibodies was specially helpful in diagnosing patients with systemic lupus erythematosis presenting with atypical features and with mixed connective tissue disease.

Anti-neutrophil cytoplasmic auto antibodies (ANCA) in Pakistani patients with systemic vasculitides

Anti-neutrophil cytoplasmic auto antibodies are directed against antigens in the neutrophil granules. Their detection by the indirect immunofluorescence clearly divides them into two distinct types, namely c-ANCA (Classical antineutrophil cytoplasmic antibody) and the p-ANCA (Perinuclear antineutrophil cytoplasmic antibody). These antibodies have been found to be useful as non-invasive markers to help establish the diagnosis in patients with systemic vasculitides. The antibodies also help in monitoring disease activity in some patients with systemic necrotising vasculitides. This study was aimed at demonstrating the utility of these auto-antibodies in the management of our patients presenting with systemic vasculitides. Fifty-six patients presenting with features of systemic vasculitides were examined over a six month period out of whom eight were found positive for these antibodies. The detection of these antibodies helped in early diagnosis and the institution of specific treatment. Six months follow-up in one patient with Wegener's granulomatosis, the disease activity related closely with the ANCA levels.

Immunohistochemical expression of CD68 antigen in human peripheral blood T cells

CD68 antigen is expressed by tissue macrophages and cells of myeloid/mononuclear lineage. CD68 is recognized by many monoclonal antibodies (mAbs), including KP1, EMB11, Y1/82A, Y2/131, Ki-M6, and Ki-M7. Using the labeled strept-avidin-biotin (LSAB) immunoperoxidase technique, we examined CD68 antigen expression in human peripheral blood T cells. The anti-CD68 mAbs KP1 and EMB11 stained virtually all fresh isolated gamma/delta T cells and CD3-CD56+ natural killer (NK) cells in a granular cytoplasmic pattern. In contrast, fresh isolated CD4+ and CD8+ T lymphocytes showed no detectable reactivity with these two anti-CD68 mAbs. However, in vitro stimulation with T-cell mitogen or recombinant interleukin-2 (rIL-2) induced expression of CD68 antigen in activated CD4+ and CD8+ T lymphocytes. Similarly, the lymphokine-activated killer (LAK) cells generated after long-term (14 to 21 days) culture of peripheral blood mononuclear cells (PBMC) in rIL-2 also showed strong granular cytoplasmic staining by the anti-CD68 antibodies. This study shows that the CD68 antigen is constitutively expressed in NK cells and gamma/delta T cells and that its expression is strongly induced in activated CD4+ and CD8+ T lymphocytes as well as LAK cells.

Cholinergic crisis following treatment of postoperative urinary retention with distigmine bromide

Distigmine bromide is a long-acting anticholinesterase, available for the treatment of postoperative urinary retention. Its effectiveness is unproven and administration may be hazardous. We describe a case in which oral distigmine bromide was used for postoperative retention, resulting in a potentially life-threatening 'cholinergic crisis'. We review the literature and conclude that the use of oral distigmine bromide in postoperative urinary retention is not justified.

Egg shell penetration tendency of different Salmonella serotypes by attached ring color method

To investigate the extent of Salmonella penetration through the egg shell, 200 eggs were dipped in red (for 3 minutes) and then in green (for 6 minutes) aqueous bland food color solution for the detection of positive penetration test areas. Each egg with positive penetration area, 5 spots of 1 cm in diameter, was marked for the attachment of steel cylinders (1 cm in diameter and height). These cylinders were filled with the test strain of Salmonella. Among 19 serotypes S. pullorum and S. gallinarum were nonmotile while the other 17 were motile. Among a total of 180 eggs (900 points) maximum (30%) penetration was in area III, where salmonellae invaded through cuticle, shell, inner and outer shell membranes, followed by area II (14.77%) and area I (4.6%). It was very well evident that penetration of salmonellae to the contents of eggs was maximum, while in area II the penetration was to outer shell membrane and in the least cases through the cuticle and shell. Penetration in area I is not significant and to some extent in area II as well, while invasion in area III is highly significant.

MHC regulation of immune responses

The major histocompatibility complex is a group of complex genes situated on the short arm of chromosome 6 in humans. They play an important role in the regulation of the immune response. Autoimmune blistering disease provides an ideal model for studying the role of MHC in autoimmunity. The diseases are organ specific, and in some of them the relevant antigen has been cloned and sequenced. Such information on the antigen will help further define the interactions of the Ag, MHC, and TCR. Use of family studies hopefully will define and localize susceptibility alleles, so that any genetic susceptibility can be identified at the molecular level. It is from these molecular perspectives that molecular therapies could be assigned to restore the immune system.

Perforin expression localizing cytotoxic lymphocytes in the intimas of coronary arteries with transplant-related accelerated arteriosclerosis

Accelerated arteriosclerosis is the major long-term complication of cardiac transplantation. It has been demonstrated recently that accelerated arteriosclerosis is caused, in part, by rejection-related, cell-mediated immunity. However, the role of cytotoxic T lymphocytes in this process is a subject of controversy. Perforin is a specific marker of functionally active cytotoxic lymphocytes because it is a functional component of the cytotoxic granules of these cells. We examined 11 coronary arteries from seven autopsied and four retransplanted heart transplant recipients for the presence of perforin-containing lymphocytes. Immunohistochemical stains for perforin were performed using a monoclonal antibody against human perforin. Eight of the 11 coronary arteries examined were found to contain perforin-positive cells. These perforin-positive cells were present in subendothelial spaces of the coronary arteries, and the staining seen was cytoplasmic and granular. The granules often were polarized to the endothelial surface. Furthermore, the cells identified were usually in close proximity to, or in direct contact with, coronary artery endothelial cells. These results suggest that cell-mediated endothelial injury by perforin-positive cytotoxic lymphocytes may contribute to the development of accelerated arteriosclerosis in heart transplant recipients.

Immunohistochemical identification of cytotoxic lymphocytes using human perforin monoclonal antibody

Perforin is a potent cytolytic pore-forming protein expressed in cytoplasmic granules of cytotoxic T lymphocytes and natural killer cells. A new monoclonal antibody raised against human perforin was used to detect both in vitro and in vivo perforin expression in cytotoxic cells. Immunohistochemical analysis of human peripheral blood mononuclear cells cultured in recombinant interleukin-2 (rIL-2) showed strong granular cytoplasmic staining of the IL-2 activated cytotoxic cells. Fresh-frozen tissue sections from patients with heart allograft rejection were also stained. Strong granular cytoplasmic staining of the mononuclear inflammatory infiltrate characteristic for perforin in cardiac allograft rejection was observed. The detection and quantitative analysis of perforin-associated cytotoxic cells by the human anti-perforin monoclonal antibody will help to evaluate the significance of these functionally distinct cytotoxic cells in human tissue.

Immunohistochemical localization of granzyme B antigen in cytotoxic cells in human tissues

Human granzyme B antigen is expressed in cytoplasmic granules of activated cytotoxic T lymphocytes and natural killer cells. Recombinant granzyme B was generated using a prokaryotic expression vector under the control of T7 transcription and translation signals. The 25-kd recombinant protein (granzyme B) was used to develop a rabbit polyclonal antiserum. Purified anti-granzyme B antibodies were used to detect the antigen expression in cytotoxic cells in human tissues. Using the avidin-biotin-complex peroxidase technique, formalin-fixed, paraffin-embedded tissue sections from patients with acute mild or moderate allograft cardiac rejection were stained. A constant cytoplasmic staining of the lymphocytic allograft infiltrate was observed. These results provide a basis for using the anti-granzyme B antibodies for detection of cytotoxic cells in human tissues. The detection and quantitative analysis of the granzyme-associated cytotoxic cells may help to evaluate the significance of these functionally distinct cytotoxic cells in human tissues associated with increased expression of cytoplasmic granule effector molecules.

Cytolysis by Ca-permeable transmembrane channels. Pore formation causes extensive DNA degradation and cell lysis

This study investigates the effect of the purified membrane pore formers, staphylococcal alpha-toxin and CTL perforin, on target cell lysis as measured by 51Cr release and on nuclear damage as measured by DNA degradation and 125IUdR release. Both pore formers cause dose-dependent cell lysis, which is accompanied by DNA release. The ratio of DNA/Cr release depends on the nature of target cell and shows the same pattern as the ratio of release of the two markers reported for CTL-mediated lysis of the same targets. DNA degradation is dependent on the presence of intracellular Ca in the target cell and is totally blocked if Ca is chelated by Quin 2 intracellularly and EGTA extracellularly. DNA degradation, in addition, is inhibited by the lysosomotropic agents NH4Cl, chloroquine, and monensin. rTNF doubles the degree of DNA degradation mediated by alpha-toxin in 3-h assays. We conclude that pore formers alone can mediate DNA degradation. In addition, they may promote the uptake of other factors and thereby accelerate their time course of action. DNA degradation by pore formers requires active target participation in a pathway that is dependent on intracellular Ca and lysosomes. These aspects of target lysis resemble CTL- and NK cell-mediated cytolysis.

Characterization of three serine esterases isolated from human IL-2 activated killer cells

Human peripheral blood mononuclear cells, activated for 14 to 20 days with 1000 U/ml rIL-2, develop strong cytotoxicity for NK sensitive and resistant targets. This process is accompanied by the acquisition of cytoplasmic granules in approximately 60% of the cells and by the expression of esterase activity cleaving the synthetic substrate BLT. The esterase activity, localized in the cytoplasmic granules, was purified and characterized. Three proteins with 3H-DFP binding activity were isolated and had the following properties. Following the proposed nomenclature by Masson et al., the esterases were named human granzymes 1, 2, and 3. Human granzyme 1 on SDS-PAGE has an unreduced relative m.w. of 43,000 and can form disulfide-linked oligomers of relative higher m.w. All forms of granzyme 1 bind 3H-DFP. Upon reduction, granzyme 1 migrates with Mr 30,000 on SDS-PAGE. Additional proteolytic fragments of Mr 24,000 and Mr 28,000 are observed in some reduced preparations. Granzyme 1 cleaves the substrate BLT and appears homologous with murine granzyme A. Human granzyme 2 has an unreduced relative m.w. of 30,000; after reduction, it migrates at Mr 32,000. Even though granzyme 2 binds 3H-DFT, it does not cleave BLT. Human granzyme 2 has properties similar to those of murine granzymes B-H. Human granzyme 3 has unreduced and reduced relative m.w. of 25,000 and 28,000, respectively. It is active in cleaving the substrate BLT. A murine analog for human granzyme 3 has not been described previously. N-terminal sequencing of the purified human granzymes revealed that human granzyme 1 is the gene product of human Hanuka factor cDNA clone and that it represents the human homolog to murine granzyme A. Similarly, human granzyme 2 revealed absolute identity with cDNA-derived N-terminal sequence of a putative human lymphocyte protease cDNA clone.

Characterization of three serine esterases isolated from human IL-2 activated killer cells

Human peripheral blood mononuclear cells, activated for 14 to 20 days with 1000 U/ml rIL-2, develop strong cytotoxicity for NK sensitive and resistant targets. This process is accompanied by the acquisition of cytoplasmic granules in approximately 60% of the cells and by the expression of esterase activity cleaving the synthetic substrate BLT. The esterase activity, localized in the cytoplasmic granules, was purified and characterized. Three proteins with 3H-DFP binding activity were isolated and had the following properties. Following the proposed nomenclature by Masson et al., the esterases were named human granzymes 1, 2, and 3. Human granzyme 1 on SDS-PAGE has an unreduced relative m.w. of 43,000 and can form disulfide-linked oligomers of relative higher m.w. All forms of granzyme 1 bind 3H-DFP. Upon reduction, granzyme 1 migrates with Mr 30,000 on SDS-PAGE. Additional proteolytic fragments of Mr 24,000 and Mr 28,000 are observed in some reduced preparations. Granzyme 1 cleaves the substrate BLT and appears homologous with murine granzyme A. Human granzyme 2 has an unreduced relative m.w. of 30,000; after reduction, it migrates at Mr 32,000. Even though granzyme 2 binds 3H-DFT, it does not cleave BLT. Human granzyme 2 has properties similar to those of murine granzymes B-H. Human granzyme 3 has unreduced and reduced relative m.w. of 25,000 and 28,000, respectively. It is active in cleaving the substrate BLT. A murine analog for human granzyme 3 has not been described previously. N-terminal sequencing of the purified human granzymes revealed that human granzyme 1 is the gene product of human Hanuka factor cDNA clone and that it represents the human homolog to murine granzyme A. Similarly, human granzyme 2 revealed absolute identity with cDNA-derived N-terminal sequence of a putative human lymphocyte protease cDNA clone.

Structure and function of human perforin

Perforin (P1) is a cytolytic protein with similarity to complement component C9. P1 has been described as a unique component of murine cytolytic T-cell and rat natural killer cell granules Previous studies indicated that human granules and P1 differed from murine granules and P1 in that they appeared to be cytolytically less active and lacked the haemolytic activity characteristic of P1. It has been suggested that P1, like C9, is under the control of the homologous restriction factor. Here we determine the primary structure of human P1, re-examine its functional properties, and address the question of homologous restriction.

Isolation and characterization of cytotoxic granules from human lymphokine (interleukin 2) activated killer cells

Cytotoxic granules were isolated from human lymphokine-activated killer (LAK) cells and analyzed for their biochemical properties. Isolated granules of approximately 85-95% purity were obtained by differential centrifugation followed by discontinuous Percoll gradient centrifugation. The murine lymphocyte granule marker N-alpha-carbamazepine-L-lysine thiobenzyl ester-esterase as well as cytotoxic activity toward the human tumor cell lines K562, Raji, Daudi, and CEM were associated with LAK granule fractions. Granule-associated N-alpha-carbamazepine-L-lysine thiobenzyl ester-esterase activity increased in recombinant interleukin 2 expanded human LAK cells in parallel with cytotoxic activity for Raji tumor cell targets. Cytotoxic LAK cell granules mediated calcium-dependent killing of the tumor cell lines K562, Raji, Daudi, and CEM. However, no calcium-dependent hemolytic activity was found. Preincubation of human granules with calcium, a treatment which totally inactivates the hemolytic and cytotoxic activity of murine lymphocyte granules [perforin 1 (P1)] had no effect on human LAK granule cytotoxicity for nucleated cells. Human LAK granules appear to contain P1 detected as cross-reactive antigen detected by mouse anti-P1 and human anti-C9 in Western blot analysis. In addition, Northern blot analysis of polyadenylated RNA isolated from human LAK cells using a murine P1 complementary DNA probe showed a cross-hybridizing 2.8- to 3.0-kilobase mRNA species identical in size to murine P1 mRNA. These results demonstrate that despite similar biochemical composition, functional differences exist between human and murine cytotoxic granules. Human LAK granules were synthesized in response to recombinant interleukin 2 activation and appeared in parallel with cytotoxicity for tumor targets, suggesting an important role for LAK granules in tumor cell cytotoxicity by human LAK cells.

Function of granule perforin and esterases in T cell-mediated reactions. Components required for delivery of molecules to target cells

Cognate T cell-mediated functions require antigen and MHC-restricted recognition of target cells. T-effector functions comprise the delivery of signals for help, for suppression, or for cell death of the target cell. In the case of the delivery of cytotoxicity and of help for B-cell antibody production, it is known that the secretory apparatus of the effector cell participates. Prior to secretion, many components of the effector cell are stored in cytoplasmic granules. Among the important and apparently constant constituents of granules are pore-forming proteins (perforins) and proteinases (granzymes). The putative role of perforin has been thought to mediate direct cytotoxicity. It is postulated here that, in addition, perforin at low concentrations may induce target-cell endocytosis through the formation of Ca channels. Localized endocytosis of the target at the contact site in turn may lead to the uptake of locally secreted effector-cell factors, such as cytotoxic factors (CTL), lymphokines (helper cells), or suppressor factors (suppressor cells). The potential importance of such a mechanism is the delivery and uptake of secreted effector-cell components into the endosomes of target cells, bypassing the need for appropriate target-cell receptors. Perforin thus may subserve two functions depending on its intragranular concentration: one, as a killer molecule, and two, as a delivery system for additional granule factors. One of the roles of esterases in T cell-mediated cognate-effector functions may be to allow recycling of the effector cell. This apparently is achieved by an active process of detachment of the effector T cell from the target cell, possibly by way of the proteolytic cleavage of adhesion molecules. Esterases are secreted, together with perforin and other factors, during granule release at the effector target-contact site, where they can cleave intercellular adhesion molecules and thus allow effector-cell recycling and attachment to new target cells. Other roles of esterases, not discussed here, may include participation directly in the cytotoxic process through uptake into the target cell. The evidence for a common intercellular molecular delivery mechanism of cognate effector T-cell function involving perforin and esterases is summarized. This concept represents a unifying hypothesis for MHC-restricted, contact-requiring, intercellular T cell-signal delivery as well as for the delivery of cytotoxicity by non-MHC-restricted T cells and natural killer cells.