We studied various biological activities of crystalline pertussigen and found that in mice as little as 0.5 ng of pertussigen induced hypersensitivity to histamine, 8 to 40 ng induced leukocytosis, 2 ng increased production of insulin, 0.1 ng increased production of immunoglobulin E and immunoglobulin Gl antibodies to hen egg albumin, 9.5 ng increased susceptibility to anaphylactic shock, and 0.5 ng increased the vascular permeability of striated muscle. We also found that in Lewis rats 20 ng of pertussigen promoted the induction of hyperacute experimental allergic encephalomyelitis. Pertussigen given intraperitoneally was toxic to mice at a dose of 546 ng. Treatment of pertussigen with glutaraldehyde eliminated this toxicity. Mice immunized with 1,700 ng of detoxified pertussigen were protected against intracerebral challenge with 3 x 104 viable Bordetella pertussis cells. When as little as 0.5 ng of pertussigen was given intravenously to mice, the increased susceptibility of the animals to histamine could still be detected 84 days later. The biological properties of crystalline pertussigen indicate its similarity to leukocytosis-promoting factor, Islet-activating protein, late-appearing toxic factor, and mouse-protective antigen of B. pertussis.

A monoclonal antibody (MCA) to enterotoxigenic Escherichia coli K99 antigen agglutinated K99+ enterotoxigenic E. coli strains B44 (09:K30;K99;F41:H-) and B41 (0101:K99;F41:H-) grown at 37°C but not at 18°C. The MCA, which was characterized as immunoglobulin G1, reacted specifically with K99 antigen in an enzyme-linked immunosorbent assay and precipitated radiolabeled K99 antigen. A total of 45 colostrum-fed and colostrum-deprived calves were used in three separate trials to determine whether the orally administered K99-specific MCA would prevent diarrhea caused by strain B44. Twenty-eight calves were fed 1 ml of mouse ascitic fluid containing K99-specific MCA at 10 h of age and were orally challenged with strain B44 at 12 to 14 h of age. Control calves either received no placebo or were fed 1 ml of mouse ascitic fluid containing fibronectin-specific MCA at 10 h of age. There was no difference in the incidence of diarrhea between the two groups after challenge. However, the severity of diarrhea, as evaluated by the proportion of calves in each group that developed severe dehydration, the degree of clinical dehydration, the degree of clinical depression, the degree of weight loss, and the duration of diarrhea after challenge was significantly reduced in calves that received the K99-specific MCA. The mortality rate was also significantly lower (P < 0.001) in the treated (29%) than in the control (82%) group. These results suggest that orally administered K99-specific MCA can prevent severe fatal enteric colibacillosis.

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Gentamicin resistance in Klebsiella pneumoniae involved in an outbreak at the Minneapolis Veterans Administration Hospital was due to a transmissible R plasmid. In addition to gentamicin, this plasmid conferred resistance to tobramycin, kanamycin, ampicillin, carbenicillin, cephalothin, chloramphenicol, and sulfathiazole. R plasmids which transferred this complex antibiogram were identified in several clinical isolates, including four different serotypes of K. pneumoniae, Escherichia coli, Enterobacter cloacae , and Proteus morganii . The covalently closed circular form of all R plasmids isolated had a sedimentation coefficient of 76S to 77S, corresponding to a molecular weight of 58 × 10 6 . The possibility that a single R plasmid was responsible for the dissemination of multiple drug resistance among all of these different clinical strains was examined by characterizing the plasmids by using Eco RI restriction endonuclease. The same 15 fragments were obtained from each of the 10 plasmids analyzed. Their molecular weights ranged from 4 × 10 5 to 11 × 10 6 . Thus, we conclude that each of the 10 plasmids present in the various clinical strains isolated from the hospital over a 7-month period originated from a common source and that R plasmid transfer was important in their spread.

Neonatal pigs were inoculated with porcine enterotoxigenic Escherichia coli 431, which carries genes for K99 fimbriae and STaP enterotoxin. Colonies of strain 431 were recovered from feces of pigs for up to 17 days after inoculation and tested for hybridization with gene probes for K9 and STaP. Variants of strain 431 that did not hybridize with the probes were considered to have lost the genes. Variants were recovered from 10 of 13 suckling pigs that survived the infection. Only 0.4% of the isolates recovered during the first 2 days after inoculation were variants. Of the isolates recovered 3 to 5 days after inoculation, 20 to 36% were variants. Variant colonies were detected more frequently among pigs in some litters than in others. The litter with the highest number of variant-shedding pigs had the dam with the highest titer of K9 antibody in her colostrum. Variants also occurred in colostrum-deprived, artificially reared pigs. However, the number of variants detected was lower and they occurred later in the course of the infection in colostrum-deprived pigs than in suckling pigs. More variants were detected and they were detected earlier in colostrum-deprived pigs fed anti-K99 monoclonal antibody than in controls fed anti-K88 monoclonal antibody. Loss of STaP appeared to be secondary to loss of K99 in that some variants lacked only K99 (K99-STaP+) and some lacked both genes (K99-STaP-), but none was of the K99+ STaP-type. Our results confirmed reports of gene loss from enterotoxigenic E. coli during infection. They are consistent with the hypothesis that variants emerge under in vivo selection pressure of K99 antibody and with the speculation that gene loss may be an important component of protection in vaccinated populations. However, the emergence of variants did not appear to play a major role in the recovery of individual pigs from clinical disease. Fimbriae (pili) and enterotoxins are virulence factors of enterotoxigenic Escherichia coli (ETEC) (1,15). Fimbriae mediate adherence of E. coli to host intestinal epithelium, and enterotoxins stimulate intestinal secretion of water and electrolytes, resulting in diarrhea. Some ETEC strains of the K88 (F4) and K99 (F5) fimbrial antigen types lose these antigens (and, apparently, the plasmids carrying the genes encoding them) during experimental infections in mice (5). Loss of K88 antigen also occurs during infections in pigs, which are natural hosts for K88+ ETEC (17,18). A human ETEC strain (6) and an enteropathogenic E. coli strain (7) have been shown to lose genes encoding heat-labile enterotoxin and an adherence factor, respectively, during infection in humans.Loss of K88 in pigs is thought to be caused by antibody, because it was detected in immunized pigs but not in control pigs (18) and because it can be induced in vitro by growth in immune colostrum (8,17,18). It has been suggested that the antibodies involved in loss of K88 are not K88 specific but rather are directed against a novel antigen(s) and act by a novel mechanism which also impedes the spread ...

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The biosynthesis of a phytotoxic glycopeptide of Corynebacterium insidiosum involves guanosine diphosphate- l -fucosyltransferase activity. This enzyme activity is most consistently associated with the cellular membranes fraction. The optimal pH for the transfer reaction is 7.5. The partially hydrolyzed toxin serves as an acceptor (primer) of l -fucose.

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