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Based on methods used for the in vitro induction of antigen-specific suppressor cells in the mouse, we have cultured Ficoll-Isopaque-separated human blood cells with high dose of antigen (100 μg/ml) in Marbrook culture vessels for 4 days. The resulting cells, when further recultured for 24 hr with a low dose of antigen (1 μg/ml), released into the supernatant material, termed 'suppressor factor', which inhibited, in an antigen-specific manner, the antibody response of mouse spleen cells in culture. The suppressor factor was analysed using immunoabsorbents, and was bound to and eluted from specific antigen, concanavalin A and lentil lectin, anti-human la antibodies, and anti-mouse suppressor factor antibodies, but was not bound to antibodies against human IgG. [ABSTRACT FROM AUTHOR]

Mononuclear cells (10-20 × 106) obtained from human peripheral blood by a standard Ficoll-Hypaque technique were suspended in RPMI 1640 media at 4°C containing 10% foetal calf serum and 7.5% dimethyl sulphoxide (DMSO). Two- millilitre aliquots were cooled at - 1°C/min in a Cryoson BV-4 programmed freezing system to - 30°C, then - 5°C/mm to - 80°C and stored in liquid nitrogen vapor. On the day of testing, cell suspensions were thawed rapidly in a 37°C water bath. DMSO was diluted slowly out of the sample and cells resuspended in fresh RPM [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. [ABSTRACT FROM AUTHOR]

Influenza virus immune human T-lymphocyte clones maintained in continuous culture in TCGF were analysed for helper activity and interleukin-2 (IL-2) production. The clones that functioned as helper cells in the production of specific antibody failed to release detectable amounts of IL-2. Conversely, the T cells that produced IL-2 were unable to provide either specific or non-specific helper function. These findings indicated the IL-2 is not an essential component for helper activity. However, phenotypic analysis revealed that both the functional subsets of T-cell clones expressed the helper phenotype in that they were T4+, T3+ and T11+ Nevertheless analysis with other antibodies revealed differences in that the IL-2 releasing clone showed greater staining with the anti-T-cell subset antibodies 9.3 and Leu 8, confirming that there is phenotype as well as functional heterogeneity within the helper inducer T-cell population. [ABSTRACT FROM AUTHOR]

Juvenile chronic arthritis (JCA) is the commonest chronic rheumatic disorder of childhood. Although conventional therapy of JCA continues to improve, many patients experience long-term ill health as a result of their disease or treatment. In adult rheumatoid arthritis (RA), similar concerns have led to the development of therapies designed to interfere in key disease processes. One such therapy is cA2, a chimeric neutralizing monoclonal antibody to the inflammatory cytokine, tumour necrosis factor-alpha (TNF-alpha). The administration of cA2 in adult RA has led to impressive short-term suppression of disease, with a good safety profile. Here, we report the first use of cA2 in childhood arthritis, choosing a patient with severe systemic-onset JCA, resistant to conventional therapies. The patient received two i.v. infusions of cA2, each at a dose of 10 mg/kg, separated by 1 week. The treatment was well tolerated and induced rapid control of fever, anorexia and serositis, together with downregulation of interleukin (IL)-6, soluble TNF receptors (sTNFR) and IL-1ra, and the acute-phase proteins C-reactive protein (CRP) and serum amyloid A (SAA). In contrast, we saw no significant improvement in joint pain or tenderness. Our findings suggest that TNF-alpha is a mediator of fever and other systemic aspects of disease in systemic JCA. TNF-alpha blockade as a treatment modality in JCA deserves further study. [ABSTRACT FROM PUBLISHER]

The generation of human antigen-specific helper cells from unprimed peripheral blood lymphoid cells in tissue culture requires the presence of the appropriate number of blood monocytes. The role of the H LA complex in this cell interaction was investigated, by using HLA-typed donors, and it was found that the monocytes had to share at least one HLA-DR specificity with the T cell donor. These experiments suggested that the genes controlling the macrophage T cell interaction are closely associated or in linkage disequilibrium with the HLA-DR region. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the efficacy, pharmacokinetics, immunogenicity, and safety of multiple infusions of a chimeric monoclonal anti-tumor necrosis factor alpha antibody (cA2) (infliximab; Remicade, Centocor, Malvern, PA) given alone or in combination with low-dose methotrexate (MTX) in rheumatoid arthritis (RA) patients., Methods: In a 26-week, double-blind, placebo-controlled, multicenter trial, 101 patients with active RA exhibiting an incomplete response or flare of disease activity while receiving low-dose MTX were randomized to 1 of 7 groups of 14-15 patients each. The patients received either intravenous cA2 at 1, 3, or 10 mg/kg, with or without MTX 7.5 mg/week, or intravenous placebo plus MTX 7.5 mg/week at weeks 0, 2, 6, 10, and 14 and were followed up through week 26., Results: Approximately 60% of patients receiving cA2 at 3 or 10 mg/kg with or without MTX achieved the 20% Paulus criteria for response to treatment, for a median duration of 10.4 to >18.1 weeks (P < 0.001 versus placebo). Patients receiving cA2 at 1 mg/kg without MTX became unresponsive to repeated infusions of cA2 (median duration 2.6 weeks; P=0.126 versus placebo). However, coadministration of cA2 at 1 mg/kg with MTX appeared to be synergistic, prolonging the duration of the 20% response in >60% of patients to a median of 16.5 weeks (P < 0.001 versus placebo; P=0.006 versus no MTX) and the 50% response to 12.2 weeks (P < 0.001 versus placebo; P=0.002 versus no MTX). Patients receiving placebo infusions plus suboptimal low-dose MTX continued to have active disease, with a Paulus response lasting a median of 0 weeks. A 70-90% reduction in the swollen joint count, tender joint count, and C-reactive protein level was maintained for the entire 26 weeks in patients receiving 10 mg/kg of cA2 with MTX. In general, treatment was well tolerated and stable blood levels of cA2 were achieved in all groups, except for the group receiving 1 mg/kg of cA2 alone, at which dosage antibodies to cA2 were observed in approximately 50% of the patients., Conclusion: Multiple infusions of cA2 were effective and well tolerated, with the best results occurring at 3 and 10 mg/kg either alone or in combination with MTX in approximately 60% of patients with active RA despite therapy with low-dose MTX. When cA2 at 1 mg/kg was given with low-dose MTX, synergy was observed. The results of the trial provide a strategy for further evaluation of the efficacy and safety of longer-term treatment with cA2.

Tumor necrosis factor-alpha (TNF-alpha), a proinflammatory cytokine known to stimulate human immunodeficiency virus type 1 (HIV-1) replication, has been implicated in the pathogenesis of HIV-1 infection. Inhibition of TNF-alpha by a chimeric humanized monoclonal antibody, cA2, was investigated in 6 HIV-1-infected patients with CD4 cell counts < 200/mm3. Two consecutive infusions of 10 mg/kg 14 days apart were well tolerated, and a prolonged serum half-life for cA2 (mean, 257 +/- 70 h) was demonstrated. Serum immunoreactive TNF-alpha concentrations fell from a mean prestudy value of 6.4 pg/mL (range, 4.2-7.9) to 1.1 pg/mL (range, 0.5-2.2) 24 h after the first infusion and returned to baseline within 7-14 days. A similar response was seen after the second infusion. No consistent changes in CD4 cell counts or plasma HIV RNA levels were observed over 42 days. Future studies evaluating the therapeutic utility of long-term TNF-alpha suppression using anti-TNF-alpha antibodies are feasible and warranted.

Objective: To assess whether monoclonal antibody to tumor necrosis factor alpha (TNF alpha) reduces endothelial activation in rheumatoid arthritis (RA)., Methods: Levels of serum E-selectin, intercellular adhesion molecule 1 (ICAM-1), and vascular cell adhesion molecule 1 (VCAM-1), and circulating leukocytes (differential counts) were measured in RA patients before and up to 4 weeks after infusion of either placebo or chimeric anti-TNF alpha antibody cA2 (1 or 10 mg/kg)., Results: Treatment with anti-TNF alpha decreased serum E-selectin and ICAM-1 levels, with the earliest detectable changes observed on days 1-3 after anti-TNF alpha infusion. No effect on VCAM-1 levels was detected. In parallel, there was a rapid and sustained increase in circulating lymphocytes. The extent of the decrease in serum E-selectin and ICAM-1 levels and the increase in lymphocyte counts was significantly higher (P < or = 0.05) in patients in whom a clinical benefit of anti-TNF alpha was observed ( > or = 20% response, by Paulus criteria, at week 4) compared with that in patients who failed to respond to anti-TNF alpha at this time point., Conclusion: We propose that decreased serum levels of adhesion molecules may reflect diminished activation of endothelial cells in the synovial microvasculature, leading to reduced migration of leukocytes into synovial joints, and thus prolonging the therapeutic effect of anti-TNF alpha in RA.

Objective: To evaluate the clinical response to and safety of single and repeat doses of a chimeric anti-CD4 monoclonal antibody, cM-T412, in patients with rheumatoid arthritis (RA) concomitantly treated with a stable regimen of low-dose methotrexate., Methods: Sixty-four patients with refractory RA, who were already receiving stable doses of methotrexate, were randomized into a multicenter, double-blind, placebo-controlled trial to receive 3 monthly treatments with either a placebo, or 5, 10, or 50 mg cM-T412, given intravenously., Results: Using > or = 50% improvement in swollen joint counts as a criterion for clinical response, 13%, 13%, 18%, and 13% of patients receiving 50, 10, or 5 mg cM-T412, or the placebo, respectively, exhibited a clinical response at 3 months of therapy. Using > or = 50% improvement in tender joint counts as a measure of clinical efficacy at 3 months, 19%, 13%, 12%, and 6% of patients receiving 50, 10, or 5 mg cM-T412, or the placebo, respectively, exhibited a clinical response. "Flu-like" symptoms (fever, chills, rigor) within 24 hours of the infusion occurred more frequently in the groups receiving 50-mg (29%) and 10-mg (31%) doses of cM-T412 than those receiving 5 mg cM-T412 (12%) or the placebo (13%). Significant CD4+ T cell depletion occurred in the 50-mg group (mean of 353 CD4+ T cells/mm3 at 6 months versus 856 CD4+ T cells/mm3 at baseline). All patients were followed up for 12 months after the final treatment; no opportunistic infectious complications occurred., Conclusion: Treatment with cM-T412 in this cohort of RA patients who were also taking methotrexate was not associated with clinical efficacy or enhanced toxicity from infectious complications, despite significant peripheral CD4+ T cell depletion.

Our in-vitro, animal, and early clinical data suggest that tumour necrosis factor alpha (TNF alpha) is an important target for specific biological therapy in rheumatoid arthritis. We report the results of repeated treatment with a chimeric monoclonal antibody to TNF alpha (cA2) in patients having disease flares. 7 patients originally enrolled in an open-label trial completed two to four cycles, each of which was followed by a good clinical response, with median improvements in the swollen-joint count and C-reactive protein exceeding 80%. cA2 may be useful therapy in the control of acute disease flares in rheumatoid arthritis and treatment programmes including cA2 may be effective in the long-term management of this disease.

Human monoclonal IgM antibody HA-1A, which recognizes the lipid A component of bacterial lipopolysaccharide (LPS), has been shown to reduce mortality in Gram negative septicemia. The vascular endothelial lining of blood vessels, which controls leucocyte traffic and activation, as well as haemostatic balance, may be one of the primary targets of LPS action during sepsis. In earlier studies we have described HA-1A-induced immune adherence of LPS to complement receptors on erythrocytes, and showed that pre-incubation with HA-1A, in the presence of complement and red blood cells, markedly reduced LPS-induced cytokine production from peripheral blood mononuclear cells. In the present study, we measured the effect of immune adherence of LPS in the presence of HA-1A on the responses of cultured endothelial cells, and found that subsequent expression of adhesion molecules such as E-selectin, ICAM-1 and VCAM-1, and secretion of the cytokines interleukin-6 and granulocyte-macrophage colony stimulating factor were markedly reduced. Moreover, the ability of LPS to increase levels of tissue factor procoagulant activity on endothelial cells was markedly diminished by LPS immune adherence to HA-1A. This decrease in endothelial activation in response to LPS following immune adherence to HA-1A may play a significant role in the protective effect of HA-1A in vivo during the course of Gram negative sepsis.

The Navy Forward Laboratory (NFL) was an advanced infectious disease laboratory which provided a theater-wide reference diagnostic capability during Operations Desert Shield/Storm. During Operation Desert Shield, when massive numbers of troops were being deployed, the NFL primarily supported medical personnel in the diagnosis and treatment of infectious diseases. During the war, the laboratory provided rapid biologic warfare diagnostic support. The NFL demonstrated the benefits of a comprehensive, on-site diagnostic laboratory when large numbers of troops are deployed to high-risk areas and demonstrated the importance of military medical research laboratories for training of scientists and physicians, threat assessment, and product development.

HA-1A is a human monoclonal IgM antibody which recognizes the lipid A component of lipopolysaccharide (LPS). This antibody has reduced mortality in the septic shock syndrome resulting from Gram negative bacteria, in which many of the manifestations are considered to be due to cellular activation and secretion of cytokines, most notably TNF-alpha. However HA-1A does not directly neutralize LPS effectively in vitro, and studies reported to date have not defined its mechanism of action. Here we demonstrate that HA-1A, which in the presence of complement promotes immune adherence, may inhibit LPS action by facilitating its sequestration on red blood cells and clearance to an extent that cytokine production is reduced. Incubation of LPS at clinically significant (pg/ml) does with HA-1A at therapeutic levels (e.g. 10 micrograms/ml) and complement resulted in LPS association with erythrocyte CR1 receptors. This reduced the ability of the residual, free LPS by 50-70% to induce the secretion of TNF-alpha, IL-1 beta and IL-6 from normal blood mononuclear cells. This mechanism is likely to be operative in vivo, and could account for the protective effect of HA-1A, and its reduction of TNF-alpha production in vivo.

The polymerase chain reaction (PCR) was used to identify spores of Bacillus anthracis. By using an assay capable of amplifying a 1247-bp fragment from the gene that encodes the edema factor of B. anthracis, as few as 10(3) copies of a plasmid containing the edema factor gene and as few as 2 x 10(4) spores were detected. Subjecting the product of this PCR to a second PCR designed to amplify a 208-bp fragment nested within the 1247-bp product improved detection to a single plasmid copy per PCR and to two spores of B. anthracis per PCR.

Four medical research teams completed ten epidemiological investigations in Djibouti and thus provided the country's Ministry of Health with valuable information on infectious disease risks. A major factor contributing to the success of the work was the high degree of cooperation between the Ministry, a United States naval medical research unit, and the World Health Organization as coordinator.

A study was conducted of travelers' diarrhea in a United States military population on deployment in Cairo, Egypt, during July and August 1987. Acute diarrhea requiring medical attention developed in 183 (4%) of 4,500 troops. A possible etiologic agent was identified in 49% of all diarrhea cases. Enteric pathogens associated with cases of diarrhea included: Enterotoxigenic Escherichia coli (17% ST-producers, 13% LT-producers, and 3% LT/ST-producers); Shigella (9%); Campylobacter spp. (2%); Salmonella (2%); and Vibrio cholerae non-01 serogroup (2%). Other enteric pathogens isolated from one episode each of diarrhea included Aeromonas hydrophila group, Plesiomonas shigelloides, and Bacillus cereus. Yersinia enterocolitica, enteroinvasive E. coli, intoxications by Clostridium perfringens and Clostridium difficile, and pathogenic enteric parasites were not found in any of the 183 patients with diarrhea. A survey of military personnel not requesting medical care indicated that up to 40% of troops may have had diarrhea during this deployment. Acute gastroenteritis is a potential cause of substantial morbidity in U.S. military personnel deployed to Egypt.

During October, 1987, 593 sera were collected from risk groups in Sudan's only major deepwater port, Port Sudan. The risk groups included prostitutes, lorry drivers and prisoners. A large proportion of the study participants practised high risk behaviour which included sexual promiscuity, medical treatment by injection, scarification and tattooing. Despite high risk behaviour and evidence of a high prevalence of hepatitis B infection, a virus transmitted in a manner similar to HIV, no study participants were positive for HIV infection. This data suggests that the prevalence of HIV infection amongst high risk groups in Port Sudan is very low. These findings confirm a lack of clinical cases of AIDS in hospitalized patients in Port Sudan and the small number of reported cases in other areas of northern Sudan.

A group of 89 prostitutes and 45 patients attending sexually transmitted disease clinics in Mogadishu, Somalia were examined for evidence of HIV infection. Both groups reported more than 1 sexual partner routinely and had sexual contacts with prostitutes. There was a significant amount of sexually transmitted diseases (STDs) in these two groups, with 11.2% and 6.7% respectively being culture positive for N. gonorrhoea. Among the prostitutes, 28.1% were positive for antibodies to T. pallidum while only 4.4% of the STD patients were positive. One isolate of N. gonorrhoea was resistant to penicillin. All study participants were negative for antibodies to HIV suggesting an extremely low prevalence of HIV in high risk behaviour groups in the capital city of Somalia.

During February 1988 a seroepidemiological survey of hepatitis A, B and D was performed in the Yemen Arab Republic. 879 sera were collected from 4 different areas; Sanaa, Hajja, Hodeidah and Taiz. The prevalence of hepatitis B surface antigen (HBsAg) was 12.7% (112/879) and some marker of hepatitis B infection was found in 45.5% (399/879) of study subjects. Only 2 (1.8%) of the 112 HBsAg positives were positive for antibody to delta hepatitis, and 9.7% (9/93) were positive for hepatitis B e antigen (HBeAg). Univariate analysis showed age, sex, qat chewing, blood transfusion, surgery and a past history of jaundice to be associated with hepatitis B infection. Using multivariate logistic regression analysis only, age (odds ratios 1.37 for HBsAg carriers and 1.51 for seropositives), a past history of jaundice (odds ratio 1.42), and combined history of blood transfusion and surgery (odds ratio 2.76) were independent predictors of infection. Hepatitis B appears to be a major health concern in the Yemen Arab Republic.

Exposure of human lymphoblastoid cell cultures to leukocyte interferon initiated the formation of membranous tubuloreticular inclusions (TRI) within the endoplasmic reticulum or perinuclear envelope. In four different cell lines originating from patients with lymphocytic cancers (Daudi, Raji, H-SB2, and SB), this unique ultrastructural effect displayed a log-linear relationship to increasing doses of interferon-alpha and was dose and time dependent. TRI morphogenesis began within 12 hr in Daudi or Raji cells exposed continuously to 500 IU of leukocyte interferon/ml, but only at 20 hr after 2- to 4-hr pulse exposures to 50 to 100 IU/ml. The TRI accumulation, determined by thin-section counts, reached maximal levels of up to 16% of cell sections within 48 to 72 hr. Experiments with Raji cells indicated a decrease in TRI formation during successive cell divisions; detection of TRI after a pulse of interferon was enhanced when DNA replication was arrested. TRI morphogenesis appeared to be independent of several other known biological actions of interferons. It manifested later than the induction of 2'-5'-oligoadenylate synthetase activity which has been correlated with establishment of the antiviral state and occurred in cell lines, including DaudiKIFNR, which resist the growth-inhibitory effects of leukocyte interferon. Participation of new polypeptide synthesis was indicated by experiments with inhibitors of transcription (actinomycin D) or translation (cycloheximide): TRI morphogenesis was blocked when actinomycin D was added 4 hr after interferon and was reduced when cycloheximide was added for the interval of 13 to 23 hr after interferon.