Bound immunoglobulin and foreign antigen in lungs of sudden infant death syndrome victims.

Lung sections from 33 infants who died suddenly and unexpectedly and were diagnosed by medical examiners as sudden infant death syndrome (SIDS) gave evidence of bound immunoglobulin G (IgG) when examined by direct fluorescent antibody technique. Ten tissues from appropriate control infants were negative. Specimens containing IgG exhibited no IgA or IgE, but three contained IgM. Sixty-one percent of lung sections with IgG contained either K or lambda antigens; the remainder contained both. The indirect fluorescent antibody technique gave similar results. Blood sera of some individuals in the study which were tested all contained both K and lambda antigens. Fluorescent-labeled immunoglobulin from one SIDS victim stained 7 of 17 SIDS lung sections tested, including his own. Labeled immunoglobulin from three mothers of SIDS victims exhibited differential selectivity in reaction with antigen in lungs of a group of 18 SIDS infants. They did not react with 10 control infant tissues. Various labeled adult sera, cord sera, and serum from an apneic child did not react with the various lungs of SIDS victims in the study.

Cytological changes related to Brucella canis variants uptake in vitro.

In this study, evidence for in vitro uptake, invasion, and cytopathogonomic effects of normal and variant strains of B. canis on tissue culture, is presented. B. canis L-phase were penicillin-induced and these microorganisms produced revertants on penicillin-free media. Tissue culture (LLC-MK2) cells were divided into different normal and variant-infected groups (I-IV), including controls. Bright-field and electron microscopic observations indicated uptake of all the strains and recognizable host cell damage (CPE) to varying degrees. At 72 h after infection, the extent of damage by L-phase was the least (55.5% CPE). The L-phase-derived revertants resulted in 80% damage; this approximates the adverse effect of normal B. canis (85%). In addition to these gross changes, various structural abnormalities, including pyknosis, nuclear disorganization, vacuolation, and karyorrhexis, were apparent. The implications of these findings and the indirect role of the L-phase in brucellosis due to B. canis are discussed.

Specific detection of mycobacteria by the immunofluorescent technique.

Using an indirect immunofluorescent technique, M. bovis var. BCG can be differentiated from M. avium in pure culture. The test involves using an unlabeled antiserum prepared against B-24, a type specific antigen of M. bovis var. BCG. In the same system M. bovis could be differentiated from other pathogenic my cobacteria in tissue sections of naturally and experimentally infected animals.

Microcapsules on Streptococcus mutans serotypes by electron microscopy.

Extracellular microcapsules have been demonstrated on cells of most serotypes of Streptococcus mutans by electron microscopy, using bacterial strains of the various serotypes and peroxidase labeled or unlabeled immune serum. A correlation was noted between the amount of capsular substance on the strains of S mutans examined and degree of antigenicity as expressed by the indirect fluorescent antibody (FA) title. A serotype d strain was shown to lose both antigenicity as determined by the FA reaction and capsular material as seen by electron microscopy with repeated in vitro passage. When 10% unheated rabbit serum was added to the medium, antigenicity and capsular material were restored.

Adsorption of Pseudomonas pseudomallei cytophilic antibodies onto rabbit alveolar macrophages.

Cytophilic antibody has been demonstrated in sera from rabbits immunized with Pseudomonas pseudomallei. This antibody passively adsorbed onto normal rabbit alveolar macrophages rendered the macrophages agglutinable by P. pseudomalei antigens and capable of displaying 'rosette' formation with polysaccharide-sensitized erythrocytes.

Interaction of Listeria monocytogenes and influenza in an animal model.

This study was designed to investigate the effects of viruses in the pathogenesis of Listeria monocytogenes. The organisms used in this study were: Listeria monocytogenes Type 1 isolated from a local fatal case; Mouse adapted influenza A/PR8/34 (HONI); Streptococcus pneumoniae Group B (U.M. Med. Ctr.) and poliovirus Type 2 MEF--G3M2. Balb-C mice were inoculated intraperitoneally with one LD50 of Listeria monocytogenes. Ten days later, the survivors were challenged intransally with 10 LD50 of influenza virus and observed for 14 days. Another set of Balb-C mice was inoculated intranasally with one LD50 of influenza virus and the survivors challenged 14 days later intraperitoneally with 10 LD50 of Listeria monocytogenes. Controls consisted of similar inoculation and challenge methods in mice using Streptococcus pneumoniae and polio virus with Listeria monocytogenes and influenza virus. Cross protection was observed only between Listeria monocytogenes and influenza virus. Cellular immunity may play a role in this interaction. This findings seem to agree with reports from others who showed cross protection between Listeria monocytogenes and other intracellular bacteria and parasites.

Interaction between Pseudomonas pseudomallei and cultured rabbit peritoneal macrophages.

The interaction between two strains of Pseudomonas pseudomallei of different virulence with normal and immune rabbit peritoneal macrophages was compared in vitro. Phagocytic activity of macrophages and bacterial survival within macrophages were dependent upon the virulence of the bacterial strain and the immune status of the macrophages. Virulent bacteria were more resistant than the less virulent strain to phagocytosis and destruction. Immune macrophages were more phagocytic and bactericidal than normal macrophages. Specific immune serum facilitated ingestion and destruction of bacteria by both normal and immune macrophages.

Induction of microbial variants of Pseudomonas pseudomallei in cultured rabbit alveolar macrophages.

Cultured alveolar and peritoneal macrophages obtained from normal and immunized rabbits were used to induce wall-defective microbial variants of Pseudomonas pseudomallei. Variants were iduced only by normal alveolar macrophages. The variants reverted to typical Pseudomonas forms either spontaneously or upon transfer into broth or agar.

Direct fluorescent-antibody method for the diagnosis of Pneumocystis carinii pneumonitis from sputa or tracheal aspirates from humans.

A direct fluorescent antibody (DFA) method was applied to sputum or tracheal aspirate from 68 patients with clinical or radiological evidence suggesting Pneumocystis carinii pneumonitis, and to 50 control patients. P. carinii was detected by DFA in specimens from 33 of the 69 clinical cases and 3 of the 50 controls. Specimens of lung from 11 of 33 DFA-positive cases were examined histologically, and 9 were positive. Four of 35 DFA-negative cases were examined histologically, and all were negative. Sputa or tracheal aspirates from 6 patients who were positive by both DFA and histological examination were examined also by methenamine silver staining; none could be diagnosed conclusively by this method. The results indicate that the DFA method is a sensitive and dependable procedure for the laboratory diagnosis of P. carinii pneumonitis in man.

Development and evaluation of a direct fluorescent antibody method for the diagnosis of Pneumocystis carinii infections in experimental animals.

Because no fully satisfactory diagnostic method has been available for use in pneumocystis infection, an attempt was made to apply the fluorescent antibody technique in the identification of Pneumocystis carinii. Hyperimmune sera were prepared in rabbits against P. carinii from human and rat sources. After proper adsorption, these antisera were conjugated with fluorescein isothiocyanate and used as reagents in a direct fluorescent antibody procedure. Each of the two reagents was found to stain trypsin-treated P. carinii organisms from either human or rat sources, indicating the presence of common antigens. Stained organisms were demonstrated in the hypopharyngeal material from rats in which pneumocystis infection had been activated by the administration of corticosteroid. From the results reported here, the procedure outlined is considered sufficiently sensitive and specific to justify tests on pneumocystis infections in man. The findings in a series of specimens from human subjects will be reported separately. The method also provides an extended approach to related research problems. The need for controls of the procedure at all points is emphasized.

Characteristics of Escherichia coli serotypes in the yanomama, a primitive indian tribe of South America.

From stool samples of isolated subjects from members of the Yanomama tribe of South America, 432 isolates of Escherichia coli were obtained from 72 individuals. Two hundred and four of these strains were typable with a standard panel of 147 O antisera; included in the above were eight enteropathogenic strains. From the untypable strains, antisera were produced, and 13 serologically distinct O serotypes were identified. These data substantiate the ubiquity of known strains of E. coli as microhabitants of man's internal environment. The finding of 13 new O serotypes suggests that, in efforts to understand the ecosystem of primitive man, the internal milieu must also be investigated.