Matthew Pollack

Botulism in an adult associated with food-borne intestinal infection with Clostridium botulinum.

Botulism is a neuroparalytic illness caused by the action of a heat-labile neurotoxin elaborated by Clostridium botulinum. Botulism in adults typically results from ingestion of preformed toxin in ...

Enhanced survival in Pseudomonas aeruginosa septicemia associated with high levels of circulating antibody to Escherichia coli endotoxin core.

We studied the relationship between serum antibodies to the cross-reactive endotoxin core of Escherichia coli and survival following Pseudomonas aeruginosa septicemia. Core glycolipid was purified from the outer cell membrane of a uridine diphosphate galactose 4-epimerase-deficient rough mutant E. coli (J5 strain), characterized, and used as the antigen in a quantitative enzyme-linked immunosorbent assay (ELISA) to measure core-specific IgG and IgM antibodies. 43 patients with Pseudomonas septicemia, among whom there was a mortality of 42%, were evaluated. Core-specific antibody concentrations in acute sera ranged from 1 to 49 micrograms/ml in the case of IgG and from 1 to 200 micrograms/ml for IgM. Core-specific antibodies of both isotypes were higher in patients who survived compared with those who succumbed to their septicemias (mean, microgram/ml +/- SEM, 26 +/- 3 vs. 14 +/- 4, P = 0.005 for IgG, and 55 +/- 12 vs. 18 +/- 5, P = 0.009 for IgM). Although total IgG levels were also higher in acute sera from survivors compared with nonsurvivors (mean, mg/dl +/- SEM, 1,120 +/- 99 vs. 694 +/- 119, P = 0.004), total IgM levels were virtually identical in the two groups (146 +/- 23 vs. 148 +/- 48, P = 0.52). Conversely, patients with core-specific IgG levels greater than 10 micrograms/ml at the onset of septicemia had better survival than those with levels less than 10 micrograms/ml (79 vs. 14%, P less than 0.001), and patients with core-specific IgM levels greater than 30 micrograms/ml had better survival than those with levels less than 30 micrograms/ml (81 vs. 44%, P = 0.01). In comparison, patients with total IgG levels greater than 1,000 mg/dl also had better survival than those with levels less than 1,000 mg/dl (82 vs. 42%, P = 0.01), while those with total IgM levels greater than 150 mg/dl showed somewhat less improvement in survival compared with those with levels less than 150 mg/dl (71 vs. 50%, P = 0.12). Core-specific IgM was highly correlated with core-specific IgG (r = 0.52), but not with type-specific anti-lipopolysaccharide (r = 0.13) or anti-toxin A (r = 0.12) antibodies, or with total IgG (r = 0.28) or IgM (r = 0.31). In contrast, core-specific IgG correlated somewhat more closely with type-specific antibodies (r = 0.36), and with total IgG (r = 0.51) and IgM (r = 0.52). Stepwise linear discriminant analysis indicated that type-specific antibody levels were the best predictor of outcome, among those antibodies examined, followed by anti-core IgM. Although anti-core IgG, anti-toxin A, and total IgG levels all correlated individually with survival, none augmented the prognostic power of type-specific antibodies in combination with anti-core IgM, which together predicted outcome accurately 73.5% of the time. Host factors not significantly associated with anti-core antibody levels included rapidly fatal underlying disease, age, sex, leukopenia, and prior treatment with cytotoxic drugs. In contrast, prior steroid therapy was associated with low levels of both core-specific IgG and IgM (P < 0.05). These data suggest cross-protective activity against P. aeruginosa septicemia of naturally occurring antibodies to the endotoxin core of E. coli. Anti-core antibodies, particularly of the IgM isotype appear to augment the more specific protective immunity engendered by antibodies to the O-specific side chains of Pseudomonas lipopolysaccharides. This cross-protective immunity likely applies to other Gram-negative pathogens as well.

Antibodies to endotoxin core determinants in normal subjects and in immune globulins for intravenous use

Abstract Experimental data suggest that antibodies directed toward the lipopolysaccharides (LPS) of Escherichia coli J5 and Salmonella minnesota R595, rough mutant strains whose LPS contains exposed core structures shared by many Gram-negative bacteria, may mediate cross-protective immunity. The possibility of using antibodies to these shared antigens for the prevention or treatment of Gram-negative sepsis prompted us to evaluate their prevalence in normal subjects and in immune globulins for intravenous use (IGIV). IgG and IgM antibodies to purified J5 and R595 LPS were measured by ELISA in plasma (or sera) obtained from healthy adults from four geographic areas and in nine IGIV preparations. Subjects from Mexico, Bangladesh, Tampa, Florida and Spokane, Washington, all had detectable antibodies to both J5 LPS and R595 LPS, although antibody levels showed considerable geographic variation. All IGIVs assayed contained high titers of anti-core antibody as well. Antibody levels were successfully increased both by screening donor plasma for high titers to R595 or J5 LPS and immunizing donors with J5 whole bacteria.

Antibacterial properties of Pseudomonas aeruginosa immunotype 1 lipopolysaccharide-specific monoclonal antibody (MAb) in a murine thigh infection model: combined effects of MAb and ceftazidime.

A murine monoclonal antibody (MAb) specific for the Pseudomonas aeruginosa immunotype 1 (It‐1) lipopolysaccharide (LPS) O‐side chain was evaluated in terms of its in vitro bactericidal opsonophagocytic activity and in vivo bacterial killing in a mouse thigh infection model. An immunoglobulin (Ig) G2a MAb Ld3–2F2, specific for It‐1 LPS, mediated in vitro complement‐dependent opsonophagocytic killing at a concentration of 10 μg/ml. MAb‐mediated, complement‐dependent killing also occurred in the absence of neutrophils at serum concentrations in excess of 20%. A remarkable synergy was observed in opsonophagocytic assays between MAb Ld3–2F2 (0.5 μg/ml) and ceftazidime (1/4 MIC). The administration of MAb Ld3–2F2 at a level of 1 μg resulted in a significant decrease in the number of bacteria in the thigh muscles of normal mice, while 100 μg of the same MAb was required for one log of reduction in the number of bacteria at the same site in neutropenic mice. The combined therapy with MAb Ld3–2F2 and ceftazidime provided a significant reduction in the density of bacteria in the thigh muscle at 9 hr post‐infection in normal and neutropenic mice as compared with those after treatment alone or with no treatment (P < 0.01). These favorable in vitro and in vivo interactions of an LPS‐specific IgG MAb and ceftazidime strongly support their potential for use in therapy, combined with an LPS‐reactive MAb and parenteral antipseudomonas β‐lactam antibiotics in the therapy of systemic Pseudomonas infections in normal and neutropenic hosts.

Administration of recombinant interleukin-11 improves the hemodynamic functions and decreases third space fluid loss in a porcine model of hemorrhagic shock and resuscitation.

We have previously demonstrated that the administration of recombinant human interleukin-11 (rhIL-11) during resuscitation improves the blood pressure in a rodent model of hemorrhagic shock. The purpose of this study was to determine whether the effects of rhIL-11 could be reproduced in a large animal model and to elucidate the impact of rhIL-11 administration on the intravascular volume status and the degree of third space fluid loss after resuscitation. A 40% blood volume hemorrhage was induced in swine (n = 45, weight of 25-35 kg) followed by a 1-h shock period and resuscitation with 0.9% sodium chloride (three times the shed blood volume). The animals were randomized to receive sham hemorrhage (group I, sham); sham hemorrhage and 50 μg/kg rhIL-11 (group II, sham + IL-11); no drug (group III, saline); or 50 μg/kg rhIL-11 (group IV, IL-11). Blood and urine samples were obtained and analyzed at baseline, at the end of hemorrhaging, and thereafter once every hour. The pleural and peritoneal effusions were precisely quantified by using clinically accepted criteria. The mean arterial pressure (MAP) was higher postresuscitation (PR) in groups I, II, and IV (71.4 ± 7.5 mmHg, 71.0 ± 8.9 mmHg, and 72.9 ± 12.3 mmHg, respectively) than in group III (59.9 ± 10.9 mmHg), and the cardiac output of PR was higher in group IV (3.46 ± 0.56 L/min) than in group III (2.99 ± 0.62 L/min; P < 0.01). The difference in MAP between groups I and II became statistically significant at 40 min after rhIL-11 injection and such a difference persisted for 90 min. After resuscitation, the urine output was higher, and the urine specific gravity and third space fluid loss were lower in group IV (1434 ± 325 mL and 1.0035, 82 ± 21 mL) than in group III (958 ± 390 mL and 1.0053, 125 ± 32 mL; P < 0.05). In a porcine model of hemorrhagic shock, the administration of rhIL-11 at the start of resuscitation significantly improved the cardiac output and blood pressure. This strategy also significantly reduced the extent of third space fluid losses while also having a favorable impact on the intravascular volume status as evidenced by the improved urine output.

Pharmacodynamic and Protective Properties of a Murine Lipopolysaccharide-Specific Monoclonal Antibody in Experimental Pseudomonas aeruginosa Pneumonia in Mice

We employed a Pseudomonas aeruginosa mouse pneumonia model to evaluate the ability of a murine monoclonal antibody (MAb) specific for the O‐side chain of P. aeruginosa Fisher Immunotype‐1 lipopolysaccharide (LPS) to achieve and sustain therapeutic levels in plasma and lung tissue, reduce bacterial populations in the lung, and prevent pneumonia‐associated mortality. An IgG3 MAb (Y1–5A4) administered to mice i.v. over a dose range of 125–1,000 μg/mouse produced plasma and lung tissue levels at 2 hr of 61–507 μg/ml and 4.3–150 μg/g, respectively. The 1,000 μg MAb dose reduced bacterial counts in lung tissue (logio cfu/g±S.D.) and blood (log10cfu/ml+S.D.) 20 hr post‐treatment (18 hr post‐challenge) from 10.00+ 0.66 to 7.66±0.91 (P<0.01) and from 4.39±0.81 to <3.0, respectively. Administration of MAb to mice in doses of 125–500 μg 2 hr prior to a 3 × 50% lethal bacterial challenge produced significant protection against death, with a calculated 50% protective dose of 167 μg. Protection was noted following administration of 1,000 μg of MAb up to 6 hr after bacterial challenge (P<0.05, compared with untreated control). Histological examination of lung tissue from infected mice revealed less acute inflammation, necrosis, and hemorrhage in MAb‐treated compared with untreated control animals and greater localization of Pseudomonas antigen within the phagocytic cells in alveolar space. These findings document the in vivo therapeutic efficacy of an LPS‐specific IgG MAb in a murine model of acute P. aeruginosa pneumonia, based in part upon the achievability of effective MAb concentrations in plasma and lung tissue.