Proposed mechanism of the inflammatory attacks in familial Mediterranean fever.

Peritoneal and synovial fluids of patients with familial Mediterranean fever lack a protein that inhibits neutrophil chemotaxis by antagonizing the complement-derived inflammatory mediator C5a. The C5a inhibitor activity was studied with the use of a C5a binding assay where peritoneal fluids were tested for their ability to inhibit recombinant C5a binding to dibutyryl cyclic adenosine monophosphate-induced U937 cells. In contrast to normal peritoneal fluids, those from patients with familial Mediterranean fever contained less than 1% C5a inhibitor activity. Gel filtration and ion exchange chromatography of peritoneal fluids from those patients did not yield any fraction that inhibited C5a binding. We suggest that the serosal tissue of patients with familial Mediterranean fever is devoid of C5a inhibitor activity and that this deficiency may explain in part the local inflammatory episodes characteristic of this disease.

Partial characterization of a C5a-inhibitor in peritoneal fluid.

We have recently described a 40-kDa protein in peritoneal fluid that neutralized the chemotactic activity of the C fraction C5a. It was deficient in peritoneal fluids of patients suffering from familial Mediterranean fever. Further characterization of the inhibitor with the use of 125I-rC5a binding to dibutyryl cAMP-induced U937 cells revealed dependence on the peritoneal fluid concentration, on the time of incubation and on temperature and pH. Fractionation of 125I-C5a on Sephadex G-50 column, before and after incubation with peritoneal fluid, revealed similar fractionation patterns despite loss of biologic activity of the treated C5a (but not its binding to polyclonal anti-C5a antibody). Analysis of rC5a by SDS-PAGE before and after treatment with partially purified C5a inhibitor, revealed slight modification of the inhibitor-treated C5a. Using various protease inhibitors (i.e., PMSF) suggested that the C5a inhibitor is a serine protease. It neutralized C5a by means of limited proteolysis which did not change C5a immunologic properties and changed only slightly its m.w. but abolished its receptor binding and chemotactic functions. It is suggested that the C5a inhibitor plays a role in the regulation of inflammation in serosal tissues and that its deficiency in familial Mediterranean fever may explain the attacks of sterile inflammation characteristic of this disease.

Association of penicillin-tolerant streptococci with epidemics of streptococcal pharyngitis in closed communities.

The association of penicillin-tolerant streptococci with reported epidemics of streptococcal pharyngitis in Israel was studied. The streptococcal strains had been isolated during 11 epidemics of community-acquired pharyngitis and 6 food-borne epidemics of pharyngitis occurring in the last 15 years. Strains were stocked lyophilized. Isolates were defined as tolerant if the MBC/MIC ratio for penicillin was greater than or equal to 32. All 122 group A streptococcal strains isolated during the epidemics of community-acquired infection showed tolerance to penicillin. In contrast, none of the 52 strains from food-borne epidemics (24 group A, 18 group C and 8 group G) was tolerant.

Food-borne outbreak of group G streptococcal sore throat in an Israeli military base.

A food-borne outbreak of sore throat caused by Lancefield group G beta-haemolytic streptococci and involving 50 persons occurred in May 1983 in an Israeli military camp. All of the patients available for clinical examination had sore throat and difficulty in swallowing. Exudative tonsillitis occurred in 46% of the patients and the body temperature was above 37.5 degrees C in 81%. The pattern of attack was uniform over the base and 37 became ill during the night and morning of the 5 May. Thirty-two (84%) of the throat cultures taken from 37 patients grew group G beta-haemolytic streptococci. Eight of 29 contacts were positive for group G beta-haemolytic streptococci and 6 of the 28 foodhandlers examined had positive cultures of the same group. The organism was also isolated from one food sample. The epidemiological and laboratory investigations indicated that a food handler, a convalescent carrier of group G streptococci, might have been the source of infection. Assumptions on the potential of non-group A streptococci to cause epidemics are discussed.

A protective human monoclonal IgA antibody produced in vitro: anti-pneumococcal antibody engendered by Epstein-Barr virus-immortalized cell line.

Human lymphocytes that produce anti-pneumococcal antibodies were separated and immortalized by Epstein-Barr virus and then cloned. One clone (NAD-Sel) produces an IgA, kappa antibody which is specific for the polysaccharides of type 8 pneumococcus, while not reactive with any of the polysaccharides derived from 24 other pneumococcal strains. The antibody, which is present in the cell supernatant as monomer and polymer, binds to protein A and does not fix complement. When incubated in vitro with type 8 pneumococci, it induces direct killing and increases the opsonization of these bacteria by mouse macrophages.

[Antibody formation in rabbits after vaccination with Streptococcus pyogenes cultured in the presence of subinhibitory concentrations of erythromycin]. / Elaboration d'anticorps chez le lapin après vaccination par Streptococcus pyogenes cultivé en présence de concentrations sub-inhibitrices d'érythromycine.

Rabbits were immunized with suspensions of Streptococcus pyogenes grown, either in the presence of subinhibitory concentrations of erythromycin (1/2 and 1/8 MIC) or without antibiotic. Over a twelve-week period, the opsonic activity of the serum and the levels of various streptococcal antibodies were determined. For the two test strains, the immune response observed was identical for the vaccine grown with 1/8 MIC erythromycin and for the control vaccine. The vaccines grown with 1/2 MIC of erythromycin induced a slower and weaker elaboration of protective antibodies.

Perinatal group B streptococcal infections in Israel.

Among 12,500 babies born in our hospital from 1977 to 1982, there was one case of neonatal sepsis due to Group B beta-hemolytic Streptococcus (GBS), an incidence which is significantly lower than that reported in Western countries (3 to 6 per 1,000 live births). Among 385 pregnant women from Jerusalem and Haifa, the vaginal colonization rate with GBS was 2.8%, in contrast with 4.6 to 36% reported in Western countries. Umbilical and ear cultures were obtained from the infants of the 85 mothers who were examined in Haifa. These cultures were repeated at 3 to 5 days of age in 60 of the 85 babies. From the above data, mother-to-infant transmission rates and neonatal nosocomial infection rates with GBS were found to be 66 and 6.6%, respectively, which correlates well with 60 to 75% and 12 to 27% reported in the literature. The low incidence of GBS neonatal sepsis in our survey may be related to the low maternal colonization rate with GBS. The low maternal colonization rate could be related to still unidentified epidemiological and environmental factors.

Epidemiology of group B streptococci in an Israeli hospital.

A technique for the rapid identification and quantification of Group B streptococci (GBS) utilizing timed coagglutination and selective broth media was designed. A prospective study of 283 mothers and 121 newborns based on this methodology revealed a GBS colonization rate of 5.3 and 4.1%, respectively. A retrospective study of 19,875 births revealed a GBS attack rate of 0.2 per 1,000 live births. Both the low colonization and the low attack rates confirm previous anecdotal reports of a low incidence of GBS colonization and disease in Israel. The technique described herein can aid in identifying those infants at risk for invasive disease.

[Effects of subinhibitory concentrations of antibiotics on the virulence of group A hemolytic Streptococci]. / Effets de concentrations sub-inhibitrices d'antibiotiques sur la virulence de Streptocoques hémolytiques du groupe A.

We have investigated the influence of subinhibitory concentrations of chloramphenicol, erythromycin, penicillin G and gentamicin on the phagocytosis and the virulence in the mouse of strains of group A beta-haemolytic streptococci. In most cases, an increase of the phagocytosis and a decrease of the virulence were shown. The maximum effect have been observed in concentration ranging from 1/2 to 1/8 of the respective MIC. In one strain, the virulence was enhanced in the presence of 1/2 and 1/4 MIC of chloramphenicol and 1/2 of erythromycin, in spite of the fact that the phagocytosis was increased in these concentrations of drugs. The importance of hyaluronic acid as virulence factor has been investigated and discussed.

Effects of subminimal inhibitory concentrations of chloramphenicol, erythromycin and penicillin on group A streptococci.

Group A streptococci strains were grown in broth containing subminimal inhibitory concentrations of chloramphenicol, erythromycin and penicillin, and tested for possible changes in colonial morphology, activity and amount of cellular and extracellular components. The following components were tested: T protein, M protein, opacity factor, lipoteichoic acid, hyaluronic acid, streptolysin S, streptolysin O, DNase, hyaluronidase and NADase. Sub-MICs of these drugs produced variable changes in the bacteria. They increased the amount of hyaluronic acid and hyaluronidase, decreased the amount of M protein, and enhanced phagocytosis and the release of lipoteichoic acid. The results indicate that sub-MICs of chloramphenicol, erythromycin and penicillin may affect the pathogenicity and toxinogenicity of group A streptococci.

Effect of leukocyte hydrolases on bacteria. XV. Inhibition by antibiotics, metabolic inhibitors, and ultraviolet irradiation of the release by leukocyte extracts, trypsin, and lysozyme of lipopolysaccharide from gram-negative bacteria.

Leukocyte extracts, trypsin, and lysozyme are all capable of releasing the bulk of the LPS from S. typhi, S. typhimurium, and E. coli. Bacteria which have been killed by heat, ultraviolet irradiation, or by a variety of metabolic inhibitors and antibiotics which affect protein, DNA, RNA, and cell wall synthesis no longer yield soluble LPS following treatment with the releasing agents. On the other hand, bacteria which are resistant to certain of the antibiotics yield nearly the full amount of soluble LPS following treatment, suggesting that certain heatlabile endogenous metabolic pathways collaborate with the releasing agents in the release of LPS from the bacteria. It is suggested that some of the beneficial effects of antibiotics on infections with gram-negative bacteria may be the prevention of massive release of endotoxin by leukocyte enzymes in inflammatory sites.

Immune response to extracellular and somatic antigens in streptococcal infection and sequelae.

The aim of the present study is to define that temporal relationships of the IgM and IgG responses to streptococcal group A carbohydrate (CHO) in rabbits and in man. Rabbits were immunized with group A streptococci and the development of anti-group A carbohydrate (ACHO) was studied. ACHO which appeared one week after the beginning of immunization belonged to the 19S class of immunoglobulins (IgM). A two- to four-fold rise in ACHO titers and immunoglobulins of the 7S class (IgG) were observed after two weeks. Three weeks after the beginning of immunization, the ACHO titer was at a maximum. In the following months no further rises in titer were seen, and the antibodies belonged mostly to the IgG class. IgM and IgG responses to streptococcal CHO and to extracellular antigens in patients with pharyngitis, acute rheumatic fever (ARF), and acute glomerulonephritis (AGN) were studied. Higher values of IgM were found in pharyngitis and AGN sera than in ARF sera, probably reflecting the interval between streprococcal infection and time of bleeding. ACHO antibodies persisted in patients' sera for long periods and belonged to IgG and IgM. This suggests a continuous, rather than a persistent, production of ACHO.

Type distribution of beta-hemolytic streptococci in Israel: a 10-year study.

A survey was carried out over 10 years on the distribution of beta-hemolytic streptococci, their identification, and the clinical implications. Curtures were typed by the conventional agglutination and precipitation methods and by enzyme production. The present survey indicates the changes in streptococcal ecology of the various serotypes. Epidemics of acute pharyngitis with complete absence of rheumatic fever provided suggestive evidence that not all group A types are associated with rheumatic fever. The survey also emphasizes the occurence of non-group A streptococci in human infection.

Antibody response to group A streptococci in an epidemic of streptococcal pharyngitis.

An epidemic of acute pharyngitis involving 280 cases occurred in a kibbutz in Israel during the fall and winter of 1972-1973. Group M and/or T type 12 streptococci was associated with the outbreak. No cases of rheumatic fever and no acute nephritis appeared in spite of the vigorous immune response to both cellular and extracellular antigens of group A streptococci documented in 50% to 80% of patients, suggesting that strain variation may be a feature of rheumatogenicity as well as nephritogenicity of group A streptococcal pharyngitis.

The effect of leukocyte hydrolases on bacteria : VI. The role played by leukocyte extracts in the sensitization of RBC by lipopolysaccharides and by the cell-sensitizing factor of group A streptococci.

The effect of proteases and of extracts of human blood leukocytes and platelets on the sensitization of human red blood cells (RBC) by lipopolysaccharides (LPS) and by the cell-sensitizing factor (SF) of group A streptococci, as determined by passive hemagglutination, was studied. While treatment of RBC by trypsin, papain (10-1500Μg/ml), and plasmin markedly increased the binding of SF to RBC as determined by the passive hemagglutination test, small amounts of leukocyte and platelet extracts (25Μg protein) failed to enhance the sensitization of RBC. On the other hand, high concentrations of leukocyte extracts (>250Μg protein) destroyed, to a large extent, the capacity of SF to sensitize RBC. The inhibitory effect of the leukocyte extracts on the SF system was optimal at neutral pH and was inhibited by heat treatment, by phenylmethyl sulfonyl fluoride (PMSF), and by liquoid, indicating the participation of neutral proteases in this reaction. Treatment of LPS with small amounts of leukocyte extracts activated the LPS molecule; this treatment could replace the alkaline treatment needed to enhance the capacity of LPS to sensitize RBC. Very high hemagglutination titers were, however, obtained when both LPS and RBC were simultaneously treated with leukocyte extracts (25Μg protein). On the other hand, larger amounts of extracts destroyed receptors for LPS on RBC. Both the enhancing and destroying capacities of the leukocyte enzyme on the LPS system were abolished by PMSF. The simultaneous sensitization of RBC by SF and LPS showed that SF is a more dominant sensitizing agent. Histone blocked receptors in RBC for both SF and LPS. The effect of the histone was abolished by trypsin. Histone also strongly bound LPS and SF and abolished to a large extent their cell-sensitizing properties. The possible role played by leukocyte extracts in the initiation of tissue damage induced by cell-sensitizing products of bacteria is discussed.