Demonstration of a blocking factor in the plasma and spinal fluid of patients with subacute sclerosing panencephalitis. I. Partial characterization

Evaluation of lymphocyte subgroups in children with subacute sclerosing panencephalitis

The aetiology of subacute sclerosing panencephalitis (SSPE) remains to be fully elucidated, although it follows infection with a hypermutant defective M-protein measles virus. This study analysed peripheral blood lymphocyte subgroups to determine their role in the pathophysiology of SSPE. It included 22 children with SSPE aged 2 - 15 years (patient group) and 22 age- and gender-matched healthy children (control group). In children < 6 years old, there were no statistically significant differences between the two groups in the proportions of lymphocytes expressing the surface markers CD3, CD8, CD19 or CD16/56, or in CD4/CD8 ratio. The proportion of CD4(+) lymphocytes in SSPE patients < 6 years of age was significantly lower compared with the control group. In children >or= 6 years old, there were no significant differences in the lymphocyte subgroups. In conclusion, these findings suggest that a low CD4(+) lymphocyte count might be responsible for SSPE in younger children.

Circulating immune complexes in patients with subacute sclerosing panencephalitis

Levels of immune complexes (ICs) in serum and cerebrospinal fluid (CSF) specimens from subacute sclerosing panencephalitis (SSPE) patients were measured using a solid-phase C1q radioimmunoassay. Single or serial serum specimens were available from 19 patients, while serial CSF specimens were available from two patients. ICs isolated from one CSF specimen by C1q immobilized to Affi-Gel were analyzed for measles virus antigens by binding of measles virus-specific antisera and by polyacrylamide gel electrophoresis followed by Western blotting. Of 78 serum specimens analyzed, 36 (46%) were positive for ICs. When the 8 patients with 3 or more serum specimens were analyzed, 6 had fluctuating levels of ICs. Two of 5 CSF specimens obtained from a patient during acute disease onset were IC-positive, while a second patient exhibited a rapid increase and decrease of IC levels in 14 CSF specimens obtained during an acute disease exacerbation. Composition analysis of ICs isolated from one of the CSF specimens revealed the presence of antigens corresponding in size to measles virus polymerase, nucleoprotein, and possibly, hemagglutinin polypeptides. These results show that SSPE patients frequently have ICs, that IC levels fluctuate in both serum and CSF, and that the ICs are at least partially composed of measles virus antigens.

Cell mediated immunity in patients with subacute sclerosing panencephalitis

Cell mediated immunity was assessed on the basis of total lymphocytes (TL), total T lymphocytes (TTL) counts, delayed skin test responses and in vitro leucocyte migration inhibition test (LIF) production in 25 patients with SSPE, classified according to the clinical stages of the disease. The patients in stage I of the disease did not show any defect in cellular immunity while the patients in stage II showed decreased TL and TTL counts, more negative skin test responses to PHA, SKSD and PPD, and unresponsiveness to SKSD of LIF production. When the patient group was evaluated as a whole, only the TL counts and the skin test responses against SKSD differed from those in the controls. These results suggest that the defects in cellular immunity demonstrated in the patients with SSPE may be due to SSPE or the measles virus itself rather than to a genetic factor predisposing patients to SSPE.

Different virus antibodies in serum and cerebrospinal fluid of patients suffering from subacute sclerosing panencephalitis

Complement fixing (CF) antibody titers to measles, parainfluenza (PI) types 1 and 3, mumps, herpes type 1, and cytomegalovirus (CMV) in serum and cerebrospinal fluid (CSF) of 33 patients with subacute sclerosing panencephalitis (SSPE) were evaluated. Results were analyzed in comparison to 11 patients with neurological diseases other than SSPE and 7 normal subjects. All SSPE patients had elevated serum and CSF measles antibody titers. The number of SSPE patients manifesting elevated titers other than measles did not reach statistical significance when compared to controls, except for PI type 1. This suggests a possible dual infection with measles and PI in SSPE. The anticomplementary effect detected in the serum and CSF of some patients indirectly suggests the presence of immune complexes.

Cellular and humoral immunity in subacute sclerosing panencephalitis

Cellular and humoral immunity was studied in 26 patients with subacute sclerosing panencephalitis. Results were compared with those of 14 normal controls and 11 patients suffering from other neurological disorders. It was shown that cellular and humoral immune responses are adequate in subacute sclerosing panencephalitis. The persistently elevated levels of serum immunoglobulin G (IgG) and IgA indicated a persistent infection, and their progressive rise in later stages correlated with the progressive nature of the illness. IgG progressively increased with the clinical stage in the cerebrospinal fluid unaccompanied by a corresponding rise in the measles antibody titer. This suggests that antigenic determinants other than those tested play a role in the production of IgG in the cerebrospinal fluid. The progressive increase in the ratio of cerebrospinal fluid to serum IgG with the advance of the disease suggests synthesis of IgG locally in the central nervous system. Elevated measles antibody titer in serum and cerebrospinal fluid is a consistent aid in the diagnosis of subacute sclerosing panencephalitis. It is more specific in cerebrospinal fluid than in serum. Its level did not vary significantly with the clinical stages or duration of illness. Depressed serum complement activity has been detected in some subacute sclerosing panencephalitis patients in whom serum levels of the third and fourth components of the complement were normal.

Prevalence of measles antibodies in patients with subacute sclerosing panencephalitis in Poland in the years 1971--1978

Between 1971 and 1978, clinical centres in four provinces of Poland reported 107 cases of subacute sclerosing panencephalitis (SSPE). This series comprised 73.8% boys and 26.2% girls. Most children were aged 6--8 years, and 66% of them had had measles in the first two years of life. As compared with a control group the geometric means of the haemagglutination-inhibiting antibodies and neutralizing antibodies were between ten and twenty times higher in SSPE patients. Determinations of the levels of antibodies carried out several times during the disease showed a rise of the titres to values as high as 1 : 128,000 in the serum and 1 : 1,024 in the cerebrospinal fluid in some cases.

Antibody-mediated destruction of virus-infected cells

This chapter describes the effect of antibody on virus-infected cells with special reference to the human system. The destruction by antibody of the infected cells through the mediation of complement is described in detail based in considerable part on the contributions of the authors. Activation of the alternative pathway by the various infected cells is of special interest. The interesting effect of the antibody-dependent cell-mediated cytotoxicity (ADCC) system involving viral antigens in cell killing is also presented. Multiple additional topics are also covered, such as the effect of antibody on the expression of viral proteins both on the surface of the cell and intracellularly. Serum antibody, produced in response to virus infections, is of major importance in preventing the spread of infection by virtue of neutralizing free virus in extracellular fluids. Virus neutralization by antibody is enhanced by complement. Antibody binding to the surface of virus-infected cells can affect virus production and release in the absence of an effector system. Immunoglobulin (IgG) antibody can mediate the destruction of virus-infected cells in conjunction with complement or cytotoxic lymphocytes. In addition, at a conceptual level there is evidence to suggest that antibody may enhance and confer specificity on basic nonspecific humoral and cell-mediated defense mechanisms.

Types of immunological failure in the "slow-virus" encephalopathies and multiple sclerosis

The pathogenesis of the slow virus encephalopathies and multiple sclerosis is reviewed within the framework of the immune response. The diseases are analyzed for the component of the immune response that appears to be crucial to the host's failure to control the disease. Thus, the absence of an immune response in the spongiform encephalopathies appears to reflect a failure of antigen recognition. Progressive multifocal leukoencephalopathy (PML), subacute sclerosing panencephalitis (SSPE), and progressive rubella panencephalitis (PRP) may result principally from a failure of effector mechanisms. In PML the failure usually occurs within the setting of an immunosuppressive illness. Conversely, in SSPE and PRP the effector failure seems to result from the nature of the host-virus interaction itself. Finally, evidence is accumulating that a defect of immunoregulation plays a significant role in multiple sclerosis.

Immunity to foot-and-mouth disease virus in guinea pigs: clinical and immune responses

Clinical and immune responses were determined for guinea pigs infected with different doses of foot-and-mouth disease virus (FMDV) type A12, strain 119, administered by different routes. Vesicles developed on the tongue or heel pad 1 day after these areas were intradermally inoculated with FMDV. However, vesicles did not develop on the feet and tongue until 3 to 4 days after the intradermal inoculation of FMDV in the flank skin or after intracardiac or subcutaneous inoculation. Infected guinea pigs developed neutralizing antibody, immediate skin reactivity of the Arthus type (4 h), and delayed skin reactivity. In addition to a delayed skin response, the presence of a cell-mediated immune response to FMDV was shown by the specific production of macrophage migration inhibition factor by peritoneal exudate cells in response to FMDV. Kinetic studies showed that neutralizing antibodies were detected at 3 days postinfection, and Arthus and delayed skin reactivity were detected at 4 days postinfection. Some guinea pigs developed either mild or subclinical infections. Regardless of the dose of infectious virus, the route of inoculation, the severity of disease, or the time of clinical onset of disease, infected guinea pigs developed similar immune responses.

Immunological aspects of cryoprecipitates from the sera of chronic HBsAg carriers

The sera of chronic hepatitis B surface antigen (HBsAg) carriers and seropositive controls were examined for the presence of immune complexes by cryoprecipitation. Cryoprecipitates (CP) were tested for HBsAg, antibody to HBsAg (anti-HBs), major classes of immunoglobulins, components of the complement system, rheumatoid factor and the ability to activate the alternative pathway of the complement system. For this analysis the methods employed included: radioimmunoassay, reverse passive haemagglutination, immunofluorescence, sucrose density gradient ultracentrifugation, agar-gel diffusion, immunoelectrophoresis, counterimmunoelectrophoresis, latex agglutination, and a haemolytic method for the detection of the activation of the alternative pathway of the complement system. HBsAg was frequently observed in the CP from chronic HBsAg carriers. No anti-HBs activity was detected in the serum of chronic HBsAg carriers. However, the CP from a number of chronic HBsAg carriers contained immunoglobulins and components of the complement system in the absence of rheumatoid factor, anti-HBs activity and were able to activate the alternative pathway of the complement system. On immunoelectrophoresis, a component of the CP reacting with anti-IgG, ANTI-IgA and anti-HBs antisera and demonstrating an altered (faster) electrophoretic mobility was observed. The nature of the CP strongly suggests the presence of circulating immune complexes in asymptomatic chronic HBaAg carriers. These immune complexes may be important in the eventual expression and outcome of clinical disease in apparently healthy carriers of HBsAg.

Absence of inhibitory effect of leprosy sera upon normal E rosetting

Inhibitory serum factors in certain infectious diseases (leprosy, tuberculosis, histoplasmosis) and malignant conditions (Hodgkin's disease, primary intracranial neoplasms) are said to be partially responsible for decreased cell-mediated immunity (CMI) and consequent anergy. The immunologic derangement in leprosy is not yet completely understood. In order to determine the effect of sera from patients with leprosy upon the rosetting capacity of normal T. lymphocytes, sera from untreated lepromatous (L) and tuberculoid (T) patients were studied. Control sera were obtained from normal volunteers and from patients with other dermatologic conditions (contact dermatitis and leg ulcer). The data indicated that test sera did not inhibit either spontaneous E rosette formation or active rosetting of normal lymphocytes.

Subacute sclerosing panencephalitis and multiple sclerosis: in vitro measles immunity and sensitization to myelin basic protein

Three children with subacute sclerosing panencephalitis (SSPE), 12 patients with multiple sclerosis (MS) and 12 healthy persons were studied by the macrophage migration inhibition factor (MIF) assay with measles and rubella antigens and with myelin basic protein. For the SSPE patients the mean migration indexes +/- standard deviation were 44.1 +/- 10.9 for measles antigen, 38.7 +/- 12.3 for rubella antigen and 49.8 +/- 25.7 for myelin basic protein; for the MS patients the indexes were 103.0 +/- 10.6, 93.8 +/- 15.0 and 89.3 +/- 19.9; and for the healthy subjects the indexes were 68.8 +/- 22.6, 77.7 +/- 31.3 and 100.1 +/- 6.5. The results of this study showed increased cellular immunity to measles and rubella in SSPE patients as compared with healthy persons, and absence of immunity to measles in MS patients. Patients with MS showed hypersensitivity to myelin basic protein during clinical exacerbations that was not associated with changes in immunity to measles, whereas all SSPE patients showed a significant response regardless to stage of illness.

Demonstration of T-cell and K-cell cytotoxicity against measles-infected cells in normal subjects, multiple sclerosis and subacute sclerosing panencephalitis

Mechanisms of cell-mediated cytotoxicity towards a human cell line persistently infected with measles virus were studied in fifteen normal (measles-immune) subjects, six patients with multiple sclerosis and three patients with subacute sclerosing panencephalitis. In normal subjects, cytotoxicity by peripheral blood mononuclear cells (PBM) in the absence of measles antibody was demonstrated, and shown by lymphocyte fractionation (removal of Fc receptor-bearing cells) to be T cell-mediated. The mean T cell-specific cytotoxic index after 12 hr incubation at the optimum target:effector cell ratio was 0·39±0·19 (1 s.d.). T-cell killing was inhibited by antibody in nine out of twelve subjects, and not significantly changed in three. Antibody enhancement of killing by PBM was found in seven out of fifteen normal subjects, but antibody did not enhance killing by a cell population depleted of Fc receptor-bearing cells. We therefore conclude that the antibody-dependent killing was mediated by Fc receptor-bearing cells (K cells). Mean cytotoxicity due to PBM in the presence of antibody at 12 hr was 0·59±0·25 (1 s.d.). Patients with multiple sclerosis showed significantly impaired T-cell cytotoxicity (mean ± 1 s.d. = 0·17±0·05), although there was overlap with the normal group, while PBM killing in the presence of antibody was normal (mean ± 1 s.d. = 0·60±0·07). Normal or low values for both types of cytotoxicity were found in three patients with subacute sclerosing panencephalitis. Contrary to evidence for several other viruses in mice, showing H-2 restriction of T-cell killing, we have demonstrated good T-cell cytotoxicity independent of shared HLA antigens between target and effector cell for measles virus infection.

Measles virus and its associated diseases

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Studies of cellular sensitization to myelin antigens in multiple sclerosis. Dissociation of MIF and LBT production in response to a peptide encephalitogenic in rhesus monkeys

The macrophage migration inhibitory factor (MIF) assay and the lymphoblastic transformation (LBT) technique were utilized simultaneously to measure immune responses to peptide Y, the 17 amino acid C-terminal fragment of basic myelin protein, in patients with multiple sclerosis (MS). Ten normals and 67 MS patients from the Montreal Neurological Hospital and affiliated institutions were examined. A prospective attempt was made to correlate the measured responses with phasic clinical activity of the disease. The LBT results indicate some degree of cellular sensitization to peptide Y which parallels the clinical course of the illness, and resembles earlier positive findings obtained with the whole basic myelin protein molecule. These findings, however, are in contrast to a negative MIF response to the Y peptide used in the present study and further contrast the positive MIF results obtained earlier using the whole protein. It is not evident from the results of the present study whether sensitization may be of any pathogenetic significance, but the findings show that differing portions of the basic myelin protein molecule may selectively stimulate specific lymphokine elaboration by sensitized lymphocytes.

Slow Infections of the Central Nervous System

This review describes the recent advances in slow infections of the nervous system emphasizing the pathogenetic aspects of these diseases. A theoretical model for the pathogenesis of subacute sclerosing panencephalitis (SSPE) is proposed, illustrating the factors that may affect host response to the measles virus and allow it to persist and produce the panencephalitis. The isolation of an oncogenic virus from progressive multifocal leukoencephalopathy (PML) has implications in the consideration of a viral etiology for some brain tumors. The agent responsible for the transmissibility of kuru and Creutzfeldt-Jakob disease (CJD) remains uncharacterized despite recent interest in viroids and abnormalities in replication of cell membranes. The epidemiological data on multiple sclerosis suggests an exposure to an infectious agent at an early age of life modified by the host response. No specific agent has been consistently associated with multiple sclerosis. Amyotrophic lateral sclerosis (ALS), Parkinson’s disease, Mollare’s meningitis and Behcet’s disease are other examples where a virus is suspect but unproven. The ability of viruses to persist in the host for months to years has linked many chronic neurologic diseases to an infectious agent, enlarging the spectrum of disease caused by viruses.

Subacute measles encephalitis complicating Hodgkin's disease in an adult

A progressive neurological illness characterized by myoclonus, motor and sensory deficits, and lethargy occurred in a patient with Hodgkin's disease and was fatal within two months. A focal inclusion cell encephalitis was demonstrated by immunohistological means to be due to measles virus. Measles encephalitis must be considered a potential opportunistic agent in the immune-compromised host.

Subacute sclerosing panencephalitis: experimental infection in primates

Measles virus isolated from the brain of a 12-year-old boy with subacute sclerosing panencephalitis caused a chronic, progressive encephalitis in experimentally infected rhesus monkeys. The infection was eventually fatal in spite of pre-existing measles immunity and a vigorous secondary antibody response in serum and cerebrospinal fluid of the infected animals. The findings provide a basis for studies into the pathogenesis and possible treatment of the human disease.

Antibody-modification of measles "in vitro" infection

While the involvement of measles-like virus with subacute sclerosing panencephalitis (SSPE) has been shown in many laboratories, the possible mechanisms by which a normal measles infection may lead to the chronic condition are unclear. The work reported here demonstrates that the growth and maintenance of Vero cells infected with the MV 30 strain of measles, in the presence of multivalent antibody, results in a redistribution of the viral antigens within the cells and an alteration in the properties of this attenuated virus which persists even after removal of the antiserum from the culture medium. It is suggested that these in vitro findings could be parallel to the situation that occurs in vivo with measles encephalitis in hamsters and human SSPE.

Pathogenic mechanisms in pulmonary fibrosis: collagen-induced migration inhibition factor production and cytotoxicity mediated by lymphocytes

The universal features of the histopathology of fibrotic lung disease are derangement of parenchymal collagen and infiltration of the parenchyma with chronic inflammatory cells. To determine if this cellular reaction might be associated with autoimmunity to a consitituent of the alveolar interstitium, peripheral blood lymphocytes were exposed to human type I collagen in vitro and evaluated for the production of migration inhibition factor and cytotoxicity. Data from 18 patients with idiopathic pulmonary fibrosis, 8 patients with pulmonary fibrosis other than idiopathic pulmonary fibrosis, 12 patients with nonfibrotic lung disease, and 9 normals demonstrated that circulating lymphocytes from more than 94% of patients with fibrotic lung disease take part in processes where the recognition of collagen results in migration inhibition factor production and lysis of collagen-coated sheep red blood cells. These collagen-induced cell-mediated phenomena are obviated with human T-lymphocyte antiserum. Collagen-induced migration inhibition factor production and cytotoxicity were found in less than 20% of patients with nonfibrotic disease and were not found in normals. Qualitatively, there was no organ (lung, skin) or species (human, rabbit) collagen specificity in these assays, but human lung alpha 2 chains were recognized more often than alpha 1(I) chains. Circulating lymphocytes from patients with fibrotic disease are present in a normal T to B ratio. These lymphocytes did not incorporate [3H]thymidine when exposed to collagen but did when exposed to T-cell mitogens. These in vitro observations suggest that circulating T-lymphocytes and lung collagen may be intimately associated in the pathogenesis of human fibrotic lung disease.

Measles virus-specific IgD antibodies in patients with subacute sclerosing panencephalitis

Indirect immunofluorescent analysis revealed that sera from five patients with subacute sclerosing panencephalitis possessed IgD antibodies directed against measles virus components in persistently infected HeLa cells. IgD levels in these sera were within the normal range. Control studies indicated that the reaction was specific for measles virus. The detection of IgD measles antibodies in these patients suggested that IgD may be involved in the pathogenesis of this viral disease.

The Raji cell radioimmune assay for detecting immune complexes in human sera

A sensitivie and simple procedure for the detection and quantitation of soluble complement (C)- fixing immune complexes in sera of patients with various disease states has been developed by utilizing C receptors on Raji cells. These cells lack membrane-bound immunoglobulin but have receptors for IgG Fc, C3b, C3d, and possibly with other C proteins. Uptake experiments showed that both aggregated human gamma globulin (AHG) and 7S IgG bound to receptors for IgG Fc; however, AHG reacted with C bound to cells only via receptors for C and this binding was much more efficient than via IgG Fc receptors. AHG was used as an in vitro model of human immune complexes and its uptake by Raji cells was quantitated by 125I-radiolabeled antihuman IgG. The limit of sensitivity of this test was 6 mug AHG/ml serum. The ability of Raji cells to detect AHG in serum depended on the amount of radioactive antibody used and the size of aggregates. The presence of an excess of C somewhat inhibited binding of AHG containing C to Raji cells. The efficient binding of AHG by receptors for C on Raji cells was used for the detection and quantitation of immune complexes in human sera. Raji cells were incubated with sera to be tested and then reacted with excess radiolabeled antihuman IgG; the amount of radioactivity bound to the washed cells was determined and referred to a standard curve of radioactive antibody uptake by cells previously incubated with increasing amounts of AHG in serum. Thereby immune complexes were detected and quantitated in serum hepatitis, systemic lupus erythematosus, vasculitis, subacute sclerosing panencephalitis, dengue hemorrhagic fever, and malignancies.

Effect of neonatal thymectomy on experimental subacute sclerosing panencephalitis in adult hamsters

Syrian golden hamsters were thymectomized in the first 48 h of life, raised, and then inoculated intracerebrally with the HBS strain of hamster-adapted subacute sclerosing panencephalitis virus when over 12 weeks old. Two groups soon become apparent; one group showed progressive neurological susmptoms and the other group remained healthy. The sick hamsters became moribund between days 8 and 17 postinoculation, and they had large amounts of complete virus in their brains, no antibodies to measles virus in their sera, and a demonstrated lack of thymus tissue. Pathological changes in the central nervous system included marked focal necrosis, numerous giant and inclusion-bearing cells, and slight inflammation. The healthy animals, killed at day 22 or 35 postinoculation, contained no central nervous system virus, moderate amounts of measles antibody in their sera, minimal or absent central nervous system pathology, and histologically identifiable remnants of thymus tissue. These studeis indicate that, in the hamster, the immune system is essential in recovering from central nervous system measles infection and that the antibody response to measles probably requires helper T lymphocytes to develop. Im the absence of antibody to measles, the virus did not undergo modification to a cell-associated state, as noted in previous hamster studies and in human subacute aclerosing panencephalitis. This model system may be useful for passive transfer studies to further clarify the effect of the n vivo immune response to acute and persistent central nervous system measles virus infections9

Immunological responsiveness of frozen-thawed human lymphocytes

Mononuclear cells (10--20 X 10(6)) obtained from human peripheral blood by a standard Ficoll-Hypaque technique were suspended in RPMI 1640 media at 4 degrees C containing 10% foetal calf serum and 7-5% dimethyl sulphoxide (DMSO). Two-millilitre aliquots were cooled at -1 degree C/min in a Cryoson BV-4 programmed freezing system to -30 degrees C, then -5 degrees C/min to -80 degrees C and stored in liquid nitrogen vapor. On the day of testing, cell suspensions were thawed rapidly in a 37 degree C water bath. DMSO was diluted slowly out of the sample and cells resuspended in fresh RPMI 1640. It was found that frozen stored human lymphocytes (FSHL) demonstrated all the characteristics of fresh unfrozen cells. These included their ability to form spontaneous rosettes with sheep erythrocytes ('E' rosettes) and sheep erythrocyte--antibody--complement rosettes ('EAC' rosettes). The presence of surface immunoglobulins and Fc receptors were shown by membrane immunofluorescence to be comparable. In addition, the results show that FSHL respond to mitogens, specific antigens; act as both stimulators and responders in the mixed lymphocyte culture reaction; and exhibit cell-mediated lymphocytotoxicity following in vitro sensitization, or against antibody-coated target cells.

Effects of canine distemper virus infection on lymphoid function in vitro and in vivo

In the present study, the immunodepressive effects of canine distemper virus (CDV) infection of dogs on two parameters of lymphocyte function, namely phytomitogen-induced cellular proliferation and skin allograft rejection, were investigated. Infection of susceptible gnotobiotic dogs with virulent R252-CDV resulted in a depression of peripheral blood lymphocyte mitogen response as measured by (3H)thymidine incorporation for up to 10 weeks after inoculation. This effect coincided with the appearance of viral antigen by immunofluorescence in leukocytes but persisted after the virus was no longer detectable. Loss of mitogen reactivity was seen in all infected dogs. However, when these same CDV-infected dogs were challenged with foreign skin allografts, no significant retention of grafts over controls was observed despite the depressed lymphocyte activity. Considering the in vitro and in vivo data it was concluded that, although immunodepressive effects of CDV were demonstrated in vitro, paralled in vivo experiments indicated that less than complete suppression of immune functions occurs during the course of CDV infection.

Human T-cell heterogeneity as delineated with a specific human thymus lymphocyte antiserum. In vitro effects on mitogen response mixed leukocyte culture, cell-mediated lymphocytotoxicity, and lymphokine production

Human peripheral blood lymphocytes (PBL) were evaluated by their responses to phytohemmagglutinin (PHA-P), concanavallin A (con-A), and pokeweed mitogen (PWM), both before and after treatment with an antiserum against human thymic lymphocyte antigens (HTLA) that had been made T-cell-specific by multiple absorptions with immunoglobulin EAC-positive lymphoblast cell lines (B cells). Cells treated with HTLA were examined for their ability to react in a mixed lymphocyte culture (MLC) and to form killer cells in a cell-mediated lymphocytotoxicity (CML) system. Sensitized cells were also examined for their ability to respond to purified protein derivative (PPD) by blastogenesis, migration inhibitory factor release (MIP), and lymphotoxin (LT) production, both before and after treatment with HTLA and complement. The HTLA was in itself highly stimulatory to PBL. However, with the addition of complement and subsequent cell destruction, a marked decrease in its stimulatory response was noted. PBL treated with HTLA and complement exhibited marked inhibition of responsiveness to con-A with little decrease in PHA-P -OR PWM stimulation except at very high concentration of HTLA. MLC reaction was inhibited only when responder cells were treated with HTLA + C'. Treatment of stimulator cells with HTLA + C' did not significantly alter the MLC response. The HTLA + C'-treated cells failed to form killer cells in the CML reaction and inhibited PPD-induced blasto-genesis from PPD-sensitized individuals; however, treatment of sensitized cells with HTLA + C' had little effects on the release of MIF and LT. It is suggested that subpopulations of T-cells carry surface antigens that bind with this specific antisera, and that the con-A-responsive cells, the responder cells in the MLC, and killer T-cells comprise a separate subset from cells responding to PHA-P or PWM, OR THE MIF-and LT-producing cells.

Cellular immunity in subacute sclerosing panencephalitis

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