Edgar E. Baker

Marrow-dependent cell function in early stages of infection with Listeria monocytogenes.

Abstract Mice were infected with either Listeria monocytogenes (LM) or Yersinia pestis EV 76 stain ( YP ), which are facultative intracellular and extracellular organisms, respectively. Bacterial growth in spleen was determined at various intervals following challenge, focusing particularly on the critical period prior to the emergence of specific immunity. Natural resistance to LM during the first 2 days was diminished by treatment of adult mice with 80 Sr or silica particles, but not by treatment with lethal total-body irradiation, cortisol, or cyclophosphamide (CY). Early stages of resistance to YP were unaffected by 80 Sr, but were reduced by lethal total-body irradiation, silica particles, cortisol, and (CY). Infant mice manifested no resistance comparable to that of adults against LM prior to 19 days of age, whereas resistance against YP was attained by 14 days of age. The data are consistent with the hypothesis that marrow-dependent (M) cells function in host defense against early stages of infection with LM but not with YP.

Effect of Antimetabolites on Growth of Endamoeba histolytica. II. Pantetheine and Coenzyme A Antagonist.

Summary 1. PAED, a pantetheine antagonist, inhibited bacteria-free cultures of E. histolytica. 2. Reversal of inhibition was possible with pantetheine and coenzyme A, but not with pantothenic acid. 3. The possible mechanism of action of PAED is discussed.

Role of O-acetyl groups in the interaction of Vi antigen with protein

1. 1. The enzyme degrading Vi antigen shows maximal activity at a substrate to protein activator ratio of 10:1. The enzyme appears to attack a Vi-protein complex rather than the free Vi antigen. The enzyme does not require an activator when the substrate lacks O-acetyl groups. 2. 2. Immunoelectrophoresis and sucrose density gradient centrifugation show that O-deacetylated Vi antigen does not form soluble complexes with albumin, and does not protect albumin from trichloroacetic acid precipitation. 3. 3. O-Acetyl groups are required for the formation of specific soluble protein-Vi antigen complexes.

Linkage Between 9 and 12 Antigens of Salmonella typhosa.

Summary The 9 and 12 antigens of S. typhosa have been specifically precipitated by either anti-9 or anti-12 sera and used to immunize rabbits. The antisera obtained contained both 9 and 12 antibodies indicating that the 9 and 12 antigens of S. typhosa are on the same molecule.

Vi Antigens of the Enterobacteriaceae. IV. Purification and Properties of Vi Antigen of S. paratyphi C.

Summary and Conclusions A method has been outlined for isolation and purification of the Vi antigen produced by S. paratyphi C. Consideration of both the chemical biological properties of this antigen indicated that it is very similar to, if not identical with, those produced by other Entcrobactcriaccac.