Investigational vaccine for Escherichia coli O157: phase 1 study of O157 O-specific polysaccharide-Pseudomonas aeruginosa recombinant exoprotein A conjugates in adults.

Escherichia coli O157 causes severe enteritis and the extraintestinal complication hemolytic-uremic syndrome. Serum IgG against the surface polysaccharide antigen, the O-specific polysaccharide of lipopolysaccharide (LPS), may confer protective immunity by lysing the inocula. In a phase 1 clinical study, three investigational vaccines were studied in 87 healthy adults. The vaccines were prepared by covalently binding E. coli O157 O-specific polysaccharide with Pseudomonas aeruginosa recombinant exoprotein A. No significant reactions were reported. Most volunteers (81%) responded with a > 4-fold increase in IgG LPS antibodies 1 week after vaccination; all volunteers responded with a > 4-fold rise at 4 weeks and this level was sustained for 26 weeks after injection. All three vaccines elicited high titers of serum bactericidal activity that roughly correlated with the serum IgG and IgM LPS antibody levels. A phase 2 study in young children is planned.

Tetrasomy 9p: tissue-limited idic(9p) in a child with mild manifestations and a normal CVS result. Report and review.

Supernumerary isochromosomes resulting in autosomal tetrasomy are rare and have been described only for 12p, 18p, and 9p. Nineteen previous cases of tetrasomy 9p have been reported, and in 6 cases, tissue-specific mosaicism was implied with the i(9p) cell line present exclusively or predominantly in blood. We report on an infant who had apparently normal chromosomes (46,XY) on CVS. He was referred for genetic evaluation because of mild developmental delay and minor anomalies. In 75% of blood cells he had an extra isodicentric 9p chromosome (pter-->q12-->pter). The interpretation of tetrasomy 9p was confirmed by elevated GALT activity. No tetrasomy 9p cells were seen in 100 skin fibroblasts. This case demonstrates the tissue specific mosaicism in tetrasomy 9p which rendered the anomaly undetectable by CVS. It also demonstrates the mild end of the clinical spectrum associated with tetrasomy 9p.

Duplication of distal 19q: clinical report and review.

We report on a 20-month-old boy with duplication of the distal part of 19q. His karyotype is 46,XY, -22, + der(22),t(19;22)(q13.3;p11.2)mat. The propositus has multiple minor anomalies, congenital heart defects, seizures, profound psychomotor retardation, and growth impairment. These characteristics are similar to those in the other 10 reported cases of distal 19q duplication and help delineate the phenotype. A review of the literature is presented.

Clinical and immunologic responses to Haemophilus influenzae type b-tetanus toxoid conjugate vaccine in infants injected at 3, 5, 7, and 18 months of age.

The safety and immunogenicity of Haemophilus influenzae type b-tetanus toxoid conjugate vaccine (Hib-TT) were evaluated in 77 healthy infants receiving injections at 3, 5, 7, and 18 months of age. No serious local or systemic reactions were noted. After the first injection the geometric mean Hib antibody level rose to 0.55 micrograms/ml, and each subsequent injection elicited a statistically significant rise in the geometric mean. The percentage of vaccinees with Hib antibody levels greater than 0.15 micrograms/ml serum was 75.5% after the first, 97.4% after the second, and 100% after the third Hib-TT injection. This percentage fell to 90.9% at 18 months of age but rose again to 100% after the fourth injection. Control infants (n = 10) injected with diphtheria-tetanus toxoid-pertussis vaccine only had nondetectable levels after the second injection. Hib-TT elicited increases of Hib antibody in all isotypes: IgG greater than IgM greater than IgA. Among IgG subclasses the highest increases were of IgG1. All vaccinated subjects had greater than 0.01 U/ml of TT antibody (estimated protective level) throughout the study. We conclude that Hib-TT, injected at 3, 5, 7, and 18 months, is safe and induces protective levels of antibodies during the age of highest incidence of meningitis caused by Hib.

Capsular polysaccharide of Haemophilus influenzae type b as a vaccine.

The inability of infants to respond to Hib PRP with the production of protective antibodies is probably in large part a consequence of the relative immaturity of their immune system. It has been reported that PRP-induced antibodies in adults are primarily of the IgG subclass 2 and that there is a higher frequency of invasive H. influenzae type b diseases among adults with limited antibody deficiencies when the IgG subclass 2 isotype is not present at normal levels. There is evidence that adult levels of IgG subclass 2 are attained later in life than are adult levels of the other subclasses. Regulation of the level of this IgG subclass will undoubtedly be an important determinant in the induction of anti-PRP antibodies in infants. It seems unlikely that simple modification of PRP, such as by increasing molecular size, would result in an increased effectiveness in younger infants, because this group is inherently unable to synthesize subclass 2 antibodies. Currently intensive efforts are being made in several laboratories to develop vaccines that conjugate PRP with proteins that are capable of eliciting a T cell-dependent response in younger children. Preliminary results of several ongoing clinical trials of vaccines of PRP conjugated with diphtheria and with tetanus toxoids indicate that these vaccines are efficacious in children as young as 7 months of age. Researchers are hopeful that vaccines can be developed to protect infants ages 2 to 3 months.

Antenatal diagnosis of a de novo paracentric inversion of chromosome 11.

A de novo paracentric inversion of chromosome 11 identified through antenatal diagnosis is described along with long-term follow-up information on the child and discussion of reported experiences with de novo inversions.

Quantitative and qualitative analyses of serum antibodies elicited in adults by Haemophilus influenzae type b and pneumococcus type 6A capsular polysaccharide-tetanus toxoid conjugates.

Covalent binding to immunogenic proteins increases the immunogenicity of the capsular polysaccharides of Haemophilus influenzae type b (Hib) and pneumococcus type 6A (Pn6A). Conjugates composed of Hib, Pn6A, or the cross-reacting Escherichia coli K100 covalently bound to tetanus toxoid (TT) were injected into young adult volunteers. Local reactions were common and were probably due to Arthus reactivity mediated by the preexisting antibodies reacting with the TT component of the conjugates. Fever occurred in about 10% of the volunteers after the first injection; no volunteers had fever after the second injection. Similar levels of Hib or Pn6A antibodies were elicited by either 50- or 100-micrograms doses or by concurrent injection of two different conjugates (Hib-TT and Pn6A-TT or Hib-TT and K100-TT). The Hib-TT elicited about a 180-fold increase in Hib antibodies, and the Pn6A-TT conjugate elicited about an 8-fold increase in Pn6A antibodies after one injection. Booster reactions were not elicited in adults; similar levels of antibodies in the five experimental groups suggested that the responses elicited by the conjugates were maximal. A one-way cross-reaction was noted as Pn6A conjugates elicited rises of Hib antibodies in 13 of 20 volunteers; only 4 of 59 volunteers immunized with Hib-TT had increases in Pn6A antibodies. The preimmunization Hib antibodies were composed of immunoglobulin M (IgM), IgA, and IgG. The postimmunization sera showed an increase in all three isotypes; the elevation of the IgG was the highest of the three isotypes. Conjugate-induced antibodies to both the polysaccharide and TT exerted biological activities that have been correlated with immunity. Adsorption of the Hib-TT onto aluminium hydroxide resulted in higher levels and an earlier Hib antibody response in infant rhesus. These results encourage the evaluation of Hib and Pn6A conjugates in human children and infants.

Anorexia and altered serotonin metabolism in a patient with argininosuccinic aciduria.

We studied serotonin metabolism in a metabolically stable 7-year-old girl with argininosuccinic aciduria who had severe anorexia. The CSF concentration of 5-hydroxyindoleacetic acid (HIAA), the metabolite of serotonin, was markedly elevated at 79 ng/ml (normal 33 +/- 11 ng/ml). Altered serotonin metabolism was also reflected in the sleep EEG, which showed decreased REM sleep. Reducing her intake of tryptophan, the precursor of serotonin, from 35 mg/kg/day to 7 mg/kg/day resulted in a decrease in CSF concentration of HIAA to 20 ng/ml and the onset of spontaneous eating for the first time in 4 1/2 years. REM sleep increased from 3% to 9.5% of total sleep time. Two days after increasing tryptophan intake to 25 mg/kg/day, spontaneous feeding stopped, associated with a rise in CSF HIAA to 45 ng/ml. Caloric/carbohydrate intake was found to affect CSF HIAA levels and food intake in an additive manner with tryptophan intake. These observations suggest that altered serotonin metabolism affected feeding behavior in this child, and that this effect could be modified by changing tryptophan or carbohydrate intake.

Enzyme-linked immunosorbent assay for detection of capsular antibodies against Haemophilus influenzae type b: comparison with radioimmunoassay.

An enzyme-linked immunosorbent assay (ELISA) is described for detection of anti-capsular antibodies against Haemophilus influenzae type b. Polyribosephosphate was covalently bonded to poly-L-lysine before adsorption to microtiter plates. ELISA immunoglobulin G and immunoglobulin M anti-polyribosephosphate antibody titers were comparable to total anti-polyribosephosphate antibody concentration determined by radioimmunoassay. The ELISA technique will be useful for further investigations of host response to infections due to H. influenzae type b but is not intended to be used as a serological method for documenting H. influenzae type b infections.

Cross-immunogenicity of pneumococcal group 9 capsular polysaccharides in adult volunteers.

Group 9 organisms (types 9N, 9A, 9L, and 9V) account for about 3 to 4% of pneumococcal disease isolates throughout the world. Types 9N and 9V comprise about 90% of the group 9 disease isolates. Type 9N is more common than type 9V in adults, and type 9V predominates in infants and children. In the United States there have been eight reported cases due to group 9 pneumococci in individuals previously vaccinated; six were type 9V and two were type 9N. To ascertain the cross-immunogenicity of group 9 polysaccharides, volunteers were injected with vaccines of monovalent types 9N, 9A, 9V, or 9L, or bivalent (9N and 9A) or trivalent (9N, 9A, and 9V) polysaccharide vaccines. Monovalent types 9N, 9V, and 9L each stimulated a 5.8- to 7.5-fold geometric mean rise, and at least 80% of the volunteers responded with a twofold or greater homologous antibody rise. Type 9V induced a 5.8-fold geometric mean rise, but only 66% of the volunteers responded with a twofold or greater homologous antibody rise. Type 9N induced only a 2.1-fold geometric increase, and only 54% of the volunteers responded with a twofold or greater rise in anti 9V antibodies. Types 9L and 9A were the most cross-immunogenic. The trivalent preparation (9N, 9A, and 9V) gave the highest geometric mean titer and seroconversion rate to each of the group 9 polysaccharides. These results suggest that the polyvalent pneumococcal vaccine with its type 9N does not induce a satisfactory anti-type 9V response and should contain additional components in order to achieve greater protection against group 9 organisms.

Gonadal dysgenesis, intra-X chromosome insertion, and possible position effect in an otherwise normal female.

A 16-year-old female was referred for cytogenetic evaluation because of primary amenorrhea. Growth, mental development, and physical examination, including secondary sexual characteristics, were normal. Cytogenetic analysis revealed one X chromosome to be consistently more metacentric than the other. Measurements indicted no significant differences between the two X's, but in the abnormal X, the increase in length of the short arm matched the decrease in length of the long arm. Banding studies suggest that region q22 through q24 of the abnormal X is inserted into region p11 of the same chromosome. Endocrine studies were indicative of gonadal dysgenesis. Since no loss of X chromosome material is involved, this patient's gonadal dysgenesis is most likely related to position effect.

Assessment of Haemophilus influenzae type b opsonins by neutrophil chemiluminescence.

A luminol-enhancement chemiluminescence assay and a radiolabeled uptake assay were developed to assess opsonins for Haemophilus influenzae type b. Opsonins in acute and convalescent sera from 17 children with H. influenzae type b meningitis, along with pooled normal human sera, were evaluated and compared with anti-polyribosephosphate antibody concentrations. Five children had a rise in the chemiluminescence-area under the curve for convalescent compared with acute sera. Patient chemiluminescence--area-under-the-curve values were significantly (P less than 0.05) more likely to exceed 50% of normal human serum values if sera contained greater than or equal to 0.1 microgram of anti-polyribosephosphate antibody per ml. Magnesium ethylene glycol tetraacetic acid chelation and heat inactivation of patient and normal human sera significantly (P less than 0.05) reduced chemiluminescence--area-under-the-curve activity. Thus, complement appears to contribute significantly to the opsonization of H. influenzae type b in sera of children. Two of nine children had increases in opsonins as assayed by 3H-labeled H. influenzae type b uptake. After natural systemic H. influenzae type b infection, young children are unable to respond acutely with an increase in anti-polyribosephosphate antibody or serum opsonic activity.

Trisomy 21 mosaicism in two successive generations in a family.

The occurrence of 46,XX/47,XX,+21 mosaicism in two successive generations implies an aetiological relationship between the 47,XX,+21 cell line of the mother and her daughter.

Association between immunoglobulin allotypes and immune responses to Haemophilus influenzae and Meningococcus polysaccharides.

Serum samples were collected from 20 healthy White and 33 Black infants before and after immunisation with three doses of diphtheria-pertussis-tetanus vaccine and with one dose of Haemophilus influenzae type b polyribose phosphate vaccine and meningococcal group A and group C polysaccharide vaccines. Antibodies to these immunogens were measured and sera were allotyped for several Gm, A2m, and Km antigens. A highly significant association was found between the Km(1) allotype and the immune responses (difference between post-immunisation and pre-immunisation antibody levels) to H. influenzae and meningococcus C polysaccharides in the White children.

Association between cross-reacting Escherichia coli K100 and disease caused by Haemophilus influenzae type b.

An unexpected association between Haemophilus influenzae type b (HIB) disease and simultaneous intestinal colonization with cross-reacting Escherichia coli K100 strains is reported. E. coli K100 were found in 18 of 92 (19.5%) HIB patients, compared with 2.5% in healthy individuals of comparable age and in none of 21 patients with meningitis caused by other bacteria. There was no difference in disease outcome, serum antibodies, and circulating HIB antigen between the E. coli K100-positive and -negative HIB patients. Possible explanations and implications of this association are discussed.

Interim report of a controlled field trial of immunization with capsular polysaccharides of Haemophilus influenzae type b and group C Neisseria meningitidis in Mecklenburg county, North Carolina (March 1974-March 1976).

Approximately 16,000 children, from two months to five years of age, were vaccinated with the capsular polysaccharide of either Haemophilus influenzae type b or group C Neisseria meningitidis. Immunizations were carried out in a double-masked, randomized manner; the doses of immunogens used were 10 microgram of H. influenzae type b polysaccharide and 25 micron g of the group CN. meningitidis polysaccharide. Immunogenicity of the two vaccines was measured in single, random specimens of blood taken from vaccinees of all ages at various intervals after immunization. A positive effect on formation of serum antibody was observed in children of all ages vaccinated with N. meningitidis polysaccharide, but increased levels of serum antibody to H. influenzae type b were observed only in recipients of that vaccine who were three years of age or older. No untoward reactions to either vaccine were noted, and both vaccines retained their original molecular size after storage for three years. Too few cases of disease have been studied for a definitive assessment of vaccine efficacy; however, a slightly protective effect against meningitis was observed for the H. influenzae type b vaccine in infants up to one year of age.

Haemophilus influenzae type b disease. Incidence in a day-care center.

Haemophilus influenzae type b (HIB) disease was observed during a 14-month period in seven of 48 infants attending a day-care center. Surveillance studies showed that 28 (58%) infants had positive nasopharyngeal cultures for HIB; four infants were colonized with HIB for nine to 12 months. Ampicillin trihydrate prophylaxis failed to reduce the HIB carrier rate. Haemophilus influenzae type b polysaccharide vaccine was administered to 34 of the children. Sera obtained prior to immunization showed detectable antibody in all infants. Only nine (26%) infants had twofold or greater rises in serum HIB antibody titers after vaccination. Antibody response was independent of age, preimmunization antibody concentration, and HIB carrier status. In one infant, HIB meningitis developed four months after she received polysaccharide vaccine. This outbreak emphasizes that HIB is highly contagious in closed populations of young, susceptible infants.

Cross-reactive antigens and immunity to diseases caused by encapsulated bacteria.

Antigenic structures may be shared among naturally occurring polymers, including proteins and polysaccharides. Proteins are polymers of amino acids. Cross-reactions between proteins are due to similarities in their overall shape rather than their individual amino acid components. Cross-reactions have been demonstrated among proteins with similar evolutionary development and structure, such as serum albumins or immunoglobulins. Polysaccharides are polymers of monosaccharides. In contrast to proteins, antigenic specificities may be conferred by mono-, di-, and trisaccharides. Since there are about 150 known naturally occurring monosaccharides, it is not unexpected that cross-reactions are demonstrable between polysaccharides from widely divergent sources.