Outer membranes (OMs) of Salmonella enteritidis, S. anatum, S. typhimurium, and S. infantis were extracted and cross-linked with glutaraldehyde to form a large macromolecular antigen. The antigen consisted of OM proteins and lipopolysaccharide and was designated 4-OMP-LPS. Polyacrylamide gel electrophoresis of extracted OMs from each serotype revealed differences in protein profiles. S. enteritidis and S. infantis possessed a greater variety of proteins than did S. anatum and S. typhimurium. Immunizations with 4-OMP-LPS in phosphate-buffered saline (4-OMP-LPS-C) and 4-OMP-LPS emulsified with muramyl dipeptide in the oil phase of a hexadecane-water emulsion (4-OMP-LPS-MDP) revealed that BALB/c mice were capable of eliciting specific primary and secondary immunoglobulin M (IgM) and IgG responses. Both antigen preparations were capable of eliciting IgM and IgG specific for the cell surfaces of each live Salmonella serotype. Also, 4-OMP-LPS-MDP and 4-OMP-LPS-C were capable of evoking a substantial anamnestic response. Adsorption studies revealed that the combined serotypes had the antigenic capacity to adsorb up to 94% of the antibodies, but 4-OMP-LPS-MDP antibodies were more effectively adsorbed than were 4-OMP-LPS-C antibodies. Adsorption of pooled antiserum with heterologous bacteria yielded a variety of adsorption profiles.

Studies have been made of human erythrocyte receptors for hemagglutinins of indeterminate specificity extracted from the seeds of the osage orange (Maclura pomifera). The seed extract agglutinates all human erythrocytes tested, both lymphocytes and granulocytes of human origin, and the erythrocytes of several animals. On the basis of hemagglutination‐inhibition tests, N‐acetyl‐D‐galactosamine is proposed as the terminal structure on human erythrocytes recognized by the Maclura lectin. Amino acids fail to inhibit, but saliva, regardless of the ABH secretor status of the donor, and human serum alpha‐globulins inhibit this lectin hemagglutination of human erythrocytes.

Two strains of mice, Swiss Webster and DBA/2Cr, were injected intraperitoneally or intravenously with varying dosages of Fusobacterium necrophorum. The ability to eliminate the infection was assessed by quantitative enumeration of the organisms present in the blood, liver, and spleen. Three-to 4-week-old DBA/2Cr mice were highly resistant to both routes of injection. The intraperitoneal injection of older mice failed to demonstrate a dose-effect relationship whereas an intravenous injection of as few as i01 cells of F. necrophorum produced progressively necrotic leg abscesses, apparently involving the lymphonodus ischiadicus which filters the site of injection. Mortality was increased with sensitization by a previous sublethal injection. Also, an ethanol-killed cell vaccine delayed the onset of lethal infection, whereas repeated sublethal live cell injections provided nonspecific protection since mice vaccinated with the growth medium were equally protected. The development of leg abscesses after intravenous injection visibly demonstrated the pathogenicity of F. necrophorum and may provide a suitable model for the evaluation ofvaccines and the effectiveness of antibiotics.

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