Interaction of plasma colloid osmotic pressure and joint fluid pressure across the endothelium-synovium layer: significance of extravascular resistance

Fluid exchanges between blood and a synovial joint cavity across two membranes in series--synovial capillary wall (fenestrated) and synovial intima (modified connective tissue). The relation between transsynovial absorption of intraarticular Krebs solution (flow Qs) and plasma colloid osmotic pressure pi p was investigated in rabbit knees perfused at constant blood pressure. Intraarticular pressure Pj was independently controlled. Linear relations between transsynovial flow and plasma colloid osmotic pressure established that transsynovial flow obeys the Starling hypothesis. However osmotic conductance, dQs/d pi p, increased 3.9 times when Pj was raised from 6 cm H2O or subatmospheric pressure to 18 cm H2O--the "yield phenomenon." Comparison of the effects of pi p and capillary pressure revealed no major change in the osmotic reflection coefficient of the blood-joint barrier to albumin upon raising Pj. The large increase in osmotic conductance was predicted quantitatively by a previous model (prediction 3.8 X) based on increases in extravascular (intimal) conductance as a function of extravascular pressure. It is argued that capillary endothelium is not the sole significant hydraulic resistance in this pathway. In the terminology of Intaglietta and de Plomb (1973) synovial capillaries are functionally intermediate between "tubes" and "tunnels."     

Kinetics of specific anti-influenza antibody production by cultured lymphocytes from patients with systemic lupus erythematosus following influenza immunization.

Specific antibody responses to influenza viral antigens produced by cultured peripheral blood mononuclear leucocytes stimulated with influenza virus or pokeweed mitogen (PWM) have been measured in seven patients with systemic lupus erythematosus (SLE) before and at time intervals after influenza immunization. Cells from two patients stimulated with influenza virus in vitro produced high levels of specific antibody 7 days after immunization. Cells from a third patient produced small amounts of specific antibody at day 14. No antibody was produced by cells from the remaining four patients. Responses were of short duration and were not detectable 1 month after immunization. Specific anti-influenza antibody was induced by PWM only from cells of those patients who responded to virus antigen although absolute levels of antibody produced were not as high. In six patients serum haemagglutination inhibiting antibody to influenza virus was measured, and all six had a greater than four-fold increase. The disparity between in vitro antibody production by peripheral blood mononuclear leucocytes and changes in serum antibody suggests that in patients with systemic lupus erythematosus, in vitro functions of peripheral blood lymphocytes do not reflect the immune system as a whole.     

Potency of antileukoprotease and alpha 1-antitrypsin to inhibit degradation of fibrinogen by adherent polymorphonuclear leukocytes from normal subjects and patients with chronic granulomatous disease.

We have studied the relative efficacy of antileukoprotease (ALP) and alpha 1-antitrypsin (alpha 1AT) to inhibit the degradation of substrate by polymorphonuclear leukocytes (PMN) attached onto a fibrinogen matrix. PMN elastase activity was assayed by radioimmunoassay of a specific 21-residue cleavage product from the amino terminus of the A alpha chain, A alpha (1-21), of fibrinogen. The adherence of PMN (1.0 x 10(6)) to a fibrinogen matrix was facilitated by incubation with recombinant tumor necrosis factor-alpha (1 nM). Subsequently, the cells were exposed to inhibitors before stimulation with cytochalasin B and formylmethionyl-leucylphenylalanine. Under these conditions, ALP inhibited A alpha (1-21) formation with an IC50 of 85 +/- 30 nM and alpha 1AT gave an IC50 of 220 +/- 98 nM (mean +/- SD). The effect of oxidant production on A alpha (1-21) formation was evaluated by comparing the effect of PMN from normal subjects with PMN from subjects with X-linked NADPH oxidase deficiency. Stimulation of PMN from the latter subjects in a similar fashion as described above resulted in the formation of 40 +/- 4 pmol/ml A alpha (1-21), or approximately twice the amount seen with cells from normal subjects. Preincubation with ALP or alpha 1AT in a concentration range between 10 to 900 nM resulted in an IC50 of 50 +/- 13 nM for ALP compared with 150 +/- 21 nM for alpha 1AT. Both inhibitors are more effective to prevent fibrinogen degradation caused by chronic granulomatous disease (CGD) PMN than by normal PMN despite the fact that CGD PMN generated more A alpha (1-21) than did normal PMN.(ABSTRACT TRUNCATED AT 250 WORDS)     

Adult schistosome cDNA libraries as a source of antigens for the study of experimental and human schistosomiasis

Protective immunity has been demonstrated in experimental schistosomiasis and is also believed to occur in man. It can be mediated by antibodies from infected animals or animals immunized with attenuated organisms. Recombinant Escherichia coli synthesizing antigenic polypeptides from the three principal species of schistosome that infect man, Schistosoma mansoni, S. japonicum and S. haematobium, have been constructed. Libraries of adult worm cDNA were prepared from each species in the expression vector lambda gt 11 and directly screened with antibodies from animals experimentally immunized with S. mansoni and S. japonicum and from humans infected with S. haematobium. The S. mansoni clones have been analysed in greatest detail. At least four different types of clones were identified. All the detected recombinant polypeptide antigens were recognised by antibodies from chronically infected mice and most were also recognised by antibodies from mice immunized with attenuated cercariae and anti-surface membrane antibodies. Clones synthesizing species-specific antigens for both S. mansoni and S. japonicum were identified by simultaneous screening of both libraries. At least three types of S. haematobium clones were identified by screening with human infection serum, most of which were species-specific. All the antigens were in the form of fusion peptides with E. coli beta-galactosidase and their expression was induced by isopropylthiogalactopyranoside. Since known protective monoclonal antibodies recognise highly glycosylated membrane proteins which cannot be identified in the form of nascent polypeptides, the direct identification of polypeptide antigens defined by their reactivity, as reported here, is an essential step in producing reagents by recombinant DNA technology, suitable for vaccination and diagnosis.     

Intensive immunosuppression in patients with disseminated sclerosis. III. Lymphocyte response in vitro.

Lymphocytes from fifteen multiple sclerosis patients gave responses to phytohaemagglutinin (PHA), conconavalin A (con A) and pokeweed mitogen (PWM) which were in the normal range. However, the responses of lymphocytes to stimulation by an allogeneic lymphoid cell line (LCL) were significantly lower in HLA-7-positive than in HLA-7-negative patients (a distinction not found in control groups). Depression of con A, PHA and PWM responses were observed during intensive immunosuppression. Responses to LCL were unaltered or increased during initial azathioprine and prednisone treatment. The depression of this response following antilymphocyte globulin (ALG) treatment was delayed in the HLA-7-positive patients. One week after the end of ALG treatment, most PHA, con A and PWM responses had returned to low normal values. Reduction of azathioprine and prednisone treatment at the end of 1 year resulted in a sharp rise in PHA and con A responses in some patients. Relapses in patients were frequently associated with low responses to LCL cells.     

The interaction of normal lymphocytes and cells from lymphoid cell lines: II. Variations relating to cell line source and lymphocyte donor

Irradiated LCL cells from several sources activated the blood lymphocytes of a panel of donors. Individual differences were present but were small. Stimulated blood lymphocytes were more potent activators (after X-irradiation) than small lymphocytes in a one-way mixed lymphocyte reaction, indicating that the state of metabolic activity of the `stimulating' lymphocyte affects the level of activation achieved. However, LCL cells incubated for several days after irradiation had not lost stimulatory capacity. Lymphocytes of pigs, rabbits, rats and mice were much less responsive than human lymphocytes. The response of animal lymphocytes generally varied with the species of origin of the serum used in the cultures.     

Peripheral blood and synovial fluid T cells differ in their response to alloantigens and recall antigens presented by dendritic cells.

Properties of T cells from inflammatory lesions were analysed by comparing the response of peripheral blood (PB) and synovial fluid (SF) T cells from 19 patients with a range of arthropathies to enriched allogeneic dendritic cells (DC) in a primary mixed leucocyte reaction (MLR). In 17 patients the proliferative response of SF T cells was significantly (P less than 0.05) less than that of PB lymphocytes. The reduced response of SF T cells was observed in all disease categories studied and could not be attributed to differences in cell number requirements or response kinetics. Addition of recombinant interleukin-2 enhanced the response of SF T cells in a dose-dependent manner. Cell mixing experiments suggested that active suppression was not the underlying mechanism of the poor MLR response of SF T cells. In contrast to the MLR response. SF T cells were able to mount vigorous proliferative responses to recall antigen presented by autologous antigen-presenting cells. The possibility is discussed that T cells compartmentalized at inflammatory lesions are a unique population with a diminished ability to interact with DC and respond to primary stimuli but an ability to respond to secondary antigenic challenge.     

Adhesion molecules are upregulated on dendritic cells isolated from human blood.

This study investigated whether the high expression of adhesion molecules on enriched preparations of circulating dendritic cells (DCs) was an intrinsic property of the cells or whether it was a consequence of the procedure used to isolate them from blood. Expression of the beta 1, beta 2 integrins (CD11/CD18 family) and other adhesion molecules on DCs in whole blood was compared with that on isolated DCs. Dendritic cells were identified by flow cytometry as leucocytes that were positive for human leucocyte antigen (HLA)-DR, but negative for CD3, CD14, CD16, CD19 and CD56. In contrast to a minority of DCs in whole blood, the majority of isolated DCs expressed the beta 2 integrins and there were a greater number of cells bearing CD44, CD54 and some of the beta 1 integrins (notably CD49b, CD49d, CD49e and CD29). An increase in the proportion of DCs bearing adhesion molecules was generally apparent at the isolation stage when mononuclear cells, which had been incubated overnight, were centrifuged on a metrizamide gradient to enrich for cells of low density. Inclusion of an inhibitor of protein glycosylation and exocytosis (brefeldin A) at all stages of separation partially prevented an increase in the percentage of DCs bearing CD18, C29 and C54 whereas the inclusion of cycloheximide (an inhibitor of polypeptide synthesis) interfered with increases in the percentage of cells bearing CD29 and CD54. Neither of these antagonists had an effect on the intensity of adhesion molecule expression. We suggest that some of the adhesion-dependent functions of isolated DCs are caused, in part, by an upregulation of surface adhesion molecules induced by the enrichment procedure.     

The in vitro transformation of thymocytes and lymphocytes from humans, rabbits and guinea-pigs and from thymomas

The response of human, rabbit and guinea-pig thymocytes in culture to blastogenic stimulants such as phytohaemagglutinin (PHA) and staphylococcal filtrate (SF) was usually considerably less than that seen with equivalent numbers of peripheral blood and lymph node lymphocytes.