Pertussis toxin and extracytoplasmic adenylate cyclase as virulence factors of Bordetella pertussis

A wild-type strain of Bordetella pertussis and a series of transposon Tn5-induced mutants deficient in the production of various factors believed to play a role in pertussis (whooping cough) were tested for virulence in infant mice. The 50% lethal dose of the wild-type strain in these animals was 2 X 10(3) bacteria. A mutant deficient in the production of the filamentous hemagglutinin was almost as virulent as the wild type. Avirulent phase mutants (i.e., deficient in the production of all toxins), a pertussis-toxin mutant, and a double mutant deficient in both hemolysin and adenylate cyclase were severely impaired in the ability to cause pertussis. These data underscore the role of pertussis toxin in the disease and provide the first direct evidence that adenylate cyclase and hemolysin are important in the pathogenesis of the infection.     

Antibody responses to defined regions of the Bordetella pertussis virulence factor pertactin

Although vaccines against Bordetella pertussis, the causative agent of whooping cough, have been in use for over 50 y, the disease has remained endemic and is still a public health problem in many countries. It has been shown that antibody titres against pertactin, which is 1 of the exposed virulence factors of pertussis, correlate with protection and pertactin is now 1 of the components of most acellular pertussis vaccines. However, little is known about the structure and location of protective epitopes on pertactin. Here we set out to investigate the antibody response using naturally occurring pertactin variants and deletion derivates. We found the N-terminus of pertactin to be immunodominant in both rabbits and humans. In contrast to vaccinated rabbits, we could not detect pertactin type-specific antibodies in human sera. In conclusion, these results show for the first time to which defined regions of the pertactin molecule antibody responses are induced. It also suggests that the amount of pertactin type-specific antibodies will not be very large and that the variation in pertactin probably will not constitute a problem in highly immune individuals.     

Protective activity of tea and catechins against Bordetella pertussis]

We examined the bactericidal activity of tea and catechins against Bordetella pertussis. Green tea, black tea and coffee showed marked bactericidal activity at their concentrations in beverages, while pu-erh tea killed the bacteria in a moderate way. (-) Epigallocatechin gallate (EGCg) and theaflavin digallate (TF3) showed also marked bactericidal activity. Green tea and black tea also effectively blocked the adhesion of B. pertussis to HeLa and CHO cells, whereas ECGg and TF3 could not. EGCg and TF3 markedly inactivated leuco-lymphocytosis promoting activity of pertussis toxin. Black tea showed slight but significant inactivation of the activity, whereas green tea showed no inactivation. These results suggest that green tea, black tea, EGCg and TF3 might act as prophylactic agents against pertussis infection.     

Hospitalization and Complications in Children under 2 Years of Age with Bordetella pertussis Infection

Summary We prospectively followed 725 children under 2 years of age with laboratory-diagnosed Bordetella pertussis infection to investigate the hospitalization rate and complications. Diagnosis was made by culture and polymerase chain reaction (PCR) from nasopharyngeal swabs in 11,016 children who presented with ≥ 7 days of cough at 63 pediatric practices in Germany. Of these children, 33 (4.5%) were hospitalized at a mean age of 4.8 months (range, 17 days to 19.5 months). Complications occurred in 16 (48%) of the 33 patients. Pneumonia developed in two (6%) children and a convulsion was observed in one (3%). Intensive care monitoring was required for 23 (70%) children. Further complications were bradycardia (21%), apnea (12%), conjunctivitis (12%), loss of weight (12%), otitis media (6%), atelectasis (3%) and dehydration (3%). Children aged 6–24 months who had not received any dose of pertussis vaccine had a ten-fold increased risk of hospitalization compared to those who had been partially or fully immunized (p < 0.05). Pertussis immunization should be given at an early point in time and completely in order to prevent severe courses of pertussis and hospitalization in young children. Received: May 4, 1999 · Revision accepted: January 20, 2000     

MTT法检测牛口蹄疫基因疫苗免疫小鼠T淋巴细胞增殖反应的研究

目的检测牛口蹄疫基因疫苗免疫小鼠后的细胞免疫水平,全面评价牛口蹄疫基因疫苗的免疫效果.方法采用MTT法检测牛口蹄疫基因疫苗免疫小鼠的T淋巴细胞增殖反应能力,以期反应出免疫小鼠的细胞免疫应答水平.结果通过MTT法检测出牛口蹄疫基因疫苗能够激发小鼠的细胞免疫应答.结论 MTT法是检测细胞免疫水平的方法之一,能够有效地检测牛口蹄疫基因疫苗免疫小鼠淋巴细胞的增殖反应.     

Consensus on the clinical and microbiologic diagnosis of Bordetella pertussis, and infection prevention. Expert Group on Pertussis Vaccination

Pertussis continues to be responsible for a significant disease burden worldwide. Although immunization practices have reduced the occurrence of the disease among children, waning vaccine- and infection-induced immunity still allows the disease to affect adolescents and adults who, in turn, can transmit the disease to non-immunized or partially immunized infants. This document is the result of a meeting in Mexico City of international experts who analyzed recent medical information in order to establish the current status of the epidemiology, diagnosis and surveillance of pertussis and, especially, the value of the dTpa booster dose in adolescents and adults as a pertussis prevention strategy in Mexico.     

Protective Effects of Human Gamma-Globulin Preparations against Experimental Aerosol Infections of Mice with Bordetella pertussis

The protective effects of three types of pooled human gamma-globulin preparations (intact: GG, S-sulfonated: GGS, and pepsin-treated: GGP) for intravenous use against experimental aerosol infection of mice with Bordetella pertussis have been evaluated. The gamma-globulin preparations GG and GGS showed significant protective activity whereas GGP did not, as evaluated by survival numbers, body weight gains and suppression of leucocytosis. GG and GGS but not GGP also possessed neutralizing activity against leucocytosis-promoting and histamine-sensitizing activities of pertussis toxin (PT). Evaluation of protective activities of GG, GGS and GGP prepared from rabbit gamma-globulin, highly immunized with PT and not containing any anti-F-HA (filamentous or agglutinin antibodies, demonstrated that anti-PT-GG and anti-PT-GGS but not anti-PT-GGP protected against experimental infection by B. pertussis. These studies showed that the protective activity was correlated with anti-PT titre but that the Fc portion of the gamma-globulin molecule is necessary for actual protection against whooping cough by B. pertussis.     

A Single Oral Immunization with Replication-Competent Adenovirus-Vectored Vaccine Induces a Neutralizing Antibody Response in Mice against Canine Distemper Virus

Canine Distemper Virus (CDV) is a fatal and highly contagious pathogen of multiple carnivores. While injectable vaccines are very effective in protecting domestic animals, their use in the wild is unrealistic. Alternative vaccines are therefore needed. Adenovirus (AdV) vectors are popular vaccine vectors due to their capacity to elicit potent humoral and cellular immune responses against the antigens they carry. In parallel, vaccines based on live human AdV-4 and -7 have been used in U.S. army for several decades as replicative oral vaccines against respiratory infection with the same viruses. Based on these observations, the use of oral administration of replication competent AdV-vectored vaccines has emerged as a promising tool especially for wildlife vaccination. Developing this type of vaccine is not easy, however, given the high host specificity of AdVs and their very low replication in non-target species. To overcome this problem, the feasibility of this approach was tested using mouse adenovirus 1 (MAV-1) in mice as vaccine vectors. First, different vaccine vectors expressing the entire or part H or F proteins of CDV were constructed. These different strains were then used as oral vaccines in BALB/c mice and the immune response to CDV was evaluated. Only the strain expressing the full length CDV H protein generated a detectable and neutralizing immune response to CDV. Secondly, using this strain, we were able to show that although this type of vaccine is sensitive to pre-existing immunity to the vector, a second oral administration of the same vaccine is able to boost the immune response against CDV. Overall, this study demonstrates the feasibility of using replicating AdVs as oral vaccine vectors to immunize against CDV in wildlife carnivores.     

Regulation of Immune Response by Autogenous Antibody against Receptor

BALB/c mice repeatedly immunized with Pneumococcus R36A vaccine produce antibodies to phosphorylcholine having the TEPC-15 myeloma idiotype (murine IgA myeloma protein that binds phosphorylcholine). The plaque-forming cell response to phosphorylcholine shows a decrease with repeated immunizations. In contrast, spleen cells from multiply immunized mice responded better in vitro than spleen cells from nonimmunized mice. The serum of animals immunized four or five times agglutinates TEPC-15-coated sheep erythrocytes. Inhibition of hemagglutination shows that the agglutinating activity is directed against the TEPC-15 idiotype. Sera from these mice, when added to cultures of normal spleen cells, specifically suppress the response to phosphorylcholine. The suppressive activity in the serum can be removed by solid absorption with TEPC-15. Evidently, repeated immunization with antigen induces two kinds of antibody responses: one directed against antigen and the other directed against the antibody to the antigen. It is proposed that this "auto" antibody against receptor is involved in the regulation of the immune response.     

Serological diagnosis of pertussis: IgM, IgA and IgG antibodies against Bordetella pertussis measured by enzyme-linked immunosorbent assay (ELISA)

Igm, IgA and IgG antibodies against Bordetella pertussis were measured by enzyme-linked immunosorbent assay (ELISA) with an ultrasonicate of formalin-killed bacteria (a mixture of strains 1, 2 and 1, 2, 3) as antigen and disposable polystyrene 9-cuvette blocks as the solid phase. The specificity properties of the assay were assessed by an inhibition technique. Of the microbes tested, only B. parapertussis was able to cause a significant inhibition. In addition, IgM and IgA antibodies against B. pertussis were only found in some sporadic cases of respiratory infections caused by other microbes. Sera, nasal swabs and cough plates were received from 198 patients with suspected whooping-cough. ELISA determinations were mostly made from only one serum sample of each patient. Paired sera were studied only from the culture-positive infants under 3 months of age. The number of positive cultures was highest in group under 3 months of age (41%), where the frequency of positive ELISA was lowest (20%). The use of paired sera strikingly increased the number of ELISA-positive individuals in this youngest patient group. In later life, the relationship between these tests changed: isolation was positive in only about 10% of the patients, whereas 29-64% yielded positive titres in ELISA. This study shows that pertussis ELISA is a valuable aid in the rapid diagnosis of pertussis, particularly of the atypical forms of the disease which mostly are culture-negative.     

Isolation of Bordetella pertussis in blood culture from a patient with multiple myeloma

Bordetella pertussis is a fastidious aerobic, Gram-negative coccobacillus that causes the classical disease of whooping cough. We present a 63 years old man with multiple myeloma who was admitted to the medical department with cough, hoarseness and fever. Bronchopneumonia was suspected and two courses of beta-lactam antibiotics had beneficial effect on his clinical condition, but his respiratory symptoms persisted. Eventually, B. pertussis grew in an aerobic blood culture. Delayed treatment with clarithromycin had little or no effect on his cough. To our knowledge this is the third reported case of B. pertussis bacteraemia. All three patients have been immunocompromized. Growth in blood culture may be slow, and prolonged incubation (at least 6 days) of the blood culture bottles and subculture to a special culture medium is necessary for isolation of B. pertussis.     

Patterns of susceptibility in an outbreak of Bordetella pertussis: Evidence from a community-based study

OBJECTIVE:

To describe an outbreak of Bordetella pertussis and to assess which factors were associated with the development of clinical pertussis in children and adults during the outbreak.

DESIGN:

A case series was described to define the epidemiology of the pertussis outbreak. A school-based survey of children was used to measure the incidence of clinical pertussis over the previous six months. Vaccination records from the local public health facility were used to look at the relationship between age and vaccination parameters, and susceptibility to clinically diagnosed pertussis. A cross-sectional survey of teachers, parents and some hospital workers was used to assess these associations in adults.

SETTING:

An outbreak of pertussis in an isolated northern community in British Columbia.

POPULATION STUDIED:

All children in the community who attend daycare, kindergarten or school, and their parents were surveyed. In addition, some health care workers and mothers of preschool children were surveyed.

MAIN RESULTS:

A total of 31 suspected cases of pertussis were identified over a three-month period. Ninety per cent of the affected children who had available vaccination records had received four or five doses of pertussis vaccine. Sixty per cent of the town''s 209 children returned completed surveys. Of these, 69% had available vaccination records. Thirty-six children (28%) reported symptoms that fit the case definition for pertussis over the previous three months. Attack rates were highest for the group of children aged 10 to 14 years. In a multivariate logistic regression analysis, receiving prophylactic medication and an increased number of years from the last vaccine dose were found to be significant predictors for developing pertussis. Thirty-four per cent of the estimated 291 adults in the community returned completed surveys. The attack rate of pertussis in the adults was only 9%. Being a member of the school staff and/or having a household contact with pertussis were significant predictors of developing pertussis.

CONCLUSIONS:

Immunity to pertussis appears to wane during childhood. Peak susceptibility appears to be during early adolescence. Adults do not seem to be at greater risk than adolescents for developing the disease, but it seems unlikely that this is due to better immunity. Rather, it is probably related to a lower risk of exposure to pertussis and a lower rate of progression to symptomatic disease when adults are infected.Key Words: Immunity, Pertussis, VaccinationVaccination against Bordetella pertussis has resulted in a dramatic reduction in the incidence of this disease in Canada. Outbreaks of pertussis, however, still occur. While many outbreaks reported elsewhere occur in populations where vaccination rates have declined, many others occur in populations with high vaccination coverage (1,2). This has not changed with the introduction of the acellular pertussis vaccine. The reasons for this are not clear, but waning immunity and the transmission of disease from adolescents and adults to younger children have been proposed as possible mechanisms (3,4). An additional constraint in studying this problem is that there is no known level of antibody that can be shown to be protective against developing pertussis (5).The idea of waning immunity has been challenged recently. De Serres and colleagues (6) found that the attack rates were the same in adolescent (12%) and adult (11%) household contacts of pertussis index cases. The authors (6) felt that this similar attack rate was more consistent with a decreasing proportion of susceptible subjects with age and with longlasting immunity. They did not suggest that this immunity comes solely from vaccination, but more likely from subclinical boosting from endemic disease. Clearly, this has implications as to the utility of introducing an adolescent booster dose to reduce further the incidence of disease in the population.In May 2000, an outbreak of pertussis was reported in an isolated northern community in British Columbia. Pertussis outbreaks have been known to occur in three- to five-year cycles in British Columbia. The last such outbreak occurred in 1996 and 1997, and resulted in more than 1100 reported cases. Increased rates of pertussis transmission had already been reported throughout the province since January 2000 (British Columbia Centre for Disease Control, internal report). By mid-May 2000, nearly 400 cases had been reported to the British Columbia Centre for Disease Control. Rates of infection were highest among young adolescents (aged 10 to 14 years), followed by older children (aged seven to nine years). The Northwest Coastal Health Services Society (the region that includes the town of Stewart) was not among those health regions that had previously reported increased numbers of cases.The town of Stewart, which has a population of approximately 500 people, has one health centre for both curative and preventive care, and is more than 150 km from the nearest settlement (excluding the hamlet of Hyder, Alaska, which is only 1.6 km away). There are three schools - a public primary school, a public secondary school and a small, private Christian school. The local health region and the Department of Health Care and Epidemiology at the University of British Columbia initiated an investigation of the pertussis outbreak in Stewart. It was thought that the relative isolation of the community and its small size would allow investigators to see whether immunization status, age and the length of time from the last vaccine dose would significantly affect disease attack rates. It was hoped that vaccination records for most of the town''s children could be verified and then compared with the results of a school-based survey for pertussis-like symptoms. As well, a survey of adults was undertaken to determine whether symptoms also occurred in this susceptible group, and whether this was related to recalled vaccination history. Disease control measures (7), including erythromycin prophylaxis of close contacts of index cases and enhanced surveillance among symptomatic individuals, had already been implemented before the present study was undertaken and were not interrupted during the course of the study.     

Effectiveness of Booster Doses of the SARS-CoV-2 Inactivated Vaccine KCONVAC against the Mutant Strains

As the COVID-19 epidemic progresses with the emergence of different SARS-CoV-2 variants, it is important to know the effectiveness of inactivated SARS-CoV-2 vaccines against the variants. To maximize efficiency, a third boost injection of the high-dose SARS-CoV-2 inactivated vaccine KCONVAC was selected for investigation. In addition to the ancestral strain, KCONVAC boost vaccination induced neutralizing antibodies and antigen-specific CD8 T cells to recognize several variants, including B.1.617.2 (Delta), B.1.1.529 (Omicron), B.1.1.7 (Alpha), B.1.351 (Beta), P.3, B.1.526.1 (Lota), B.1.526.2, B.1.618, and B.1.617.3. Both humoral and cellular immunity against variants were lower than those of ancestral variants but continued to increase from day 0 to day 7 to day 50 after boost vaccination. Fifty days post-boost, the KCONVAC-vaccinated CD8 T-cell level reached 1.23-, 2.59-, 2.53-, and 1.01-fold that of convalescents against ancestral, Delta, Omicron and other SARS-CoV-2 variants, respectively. Our data demonstrate the importance of KCONVAC boosters to broaden both humoral and cellular immune responses against SARS-CoV-2 variants.     

Patterns of susceptibility in an outbreak of Bordetella pertussis: Evidence from a community-based study.

OBJECTIVE: To describe an outbreak of Bordetella pertussis and to assess which factors were associated with the development of clinical pertussis in children and adults during the outbreak. DESIGN: A case series was described to define the epidemiology of the pertussis outbreak. A school-based survey of children was used to measure the incidence of clinical pertussis over the previous six months. Vaccination records from the local public health facility were used to look at the relationship between age and vaccination parameters, and susceptibility to clinically diagnosed pertussis. A cross-sectional survey of teachers, parents and some hospital workers was used to assess these associations in adults. SETTING: An outbreak of pertussis in an isolated northern community in British Columbia. POPULATION STUDIED: All children in the community who attend daycare, kindergarten or school, and their parents were surveyed. In addition, some health care workers and mothers of preschool children were surveyed. MAIN RESULTS: A total of 31 suspected cases of pertussis were identified over a three-month period. Ninety per cent of the affected children who had available vaccination records had received four or five doses of pertussis vaccine. Sixty per cent of the town's 209 children returned completed surveys. Of these, 69% had available vaccination records. Thirty-six children (28%) reported symptoms that fit the case definition for pertussis over the previous three months. Attack rates were highest for the group of children aged 10 to 14 years. In a multivariate logistic regression analysis, receiving prophylactic medication and an increased number of years from the last vaccine dose were found to be significant predictors for developing pertussis. Thirty-four per cent of the estimated 291 adults in the community returned completed surveys. The attack rate of pertussis in the adults was only 9%. Being a member of the school staff and/or having a household contact with pertussis were significant predictors of developing pertussis. CONCLUSIONS: Immunity to pertussis appears to wane during childhood. Peak susceptibility appears to be during early adolescence. Adults do not seem to be at greater risk than adolescents for developing the disease, but it seems unlikely that this is due to better immunity. Rather, it is probably related to a lower risk of exposure to pertussis and a lower rate of progression to symptomatic disease when adults are infected.