Safety data from the MenB-FHbp clinical development program in healthy individuals aged 10 years and older

BACKGROUND

The MenB-FHbp vaccine (Trumenba®) is licensed in various countries for the prevention of meningococcal serogroup B disease in individuals ≥ 10 years of age. The clinical development program included 11 completed trials where, in each trial, MenB-FHbp had an acceptable safety profile after a primary vaccination series was administered to individuals 10-65 years of age. However, the detection of potential rare events was limited because of individual clinical trial size. The current safety analysis evaluates pooled reactogenicity and other adverse events (AEs) reported in these trials to identify new safety signals not detectable in individual trials.

METHODS

Eleven trials contributed safety data, of which 10 recorded local and systemic reactogenicity events; 8 of the trials were controlled, and reactogenicity data were pooled for 7 of these 8 trials. Additional AE evaluations included immediate AEs (IAEs), medically attended AEs (MAEs), serious AEs (SAEs), newly diagnosed chronic medical conditions (NDCMCs), and autoimmune or neuroinflammatory conditions.

RESULTS

Local and systemic reactions were more frequent in the MenB-FHbp group (n = 15,294) compared with controls (n = 5509), although most reactions were transient and mild to moderate in severity. Frequencies of IAEs, SAEs, MAEs, NDCMCs, and autoimmune or neuroinflammatory conditions were similar between the MenB-FHbp and control groups.

CONCLUSIONS

MenB-FHbp demonstrated a favorable safety and tolerability profile in the clinical development program of > 15,000 vaccine recipients ≥ 10 years of age. No new safety signals were identified in the pooled analysis compared with data from the individual trials. Continued postmarketing safety surveillance is important for the identification of rare events. Clinicaltrials.gov: NCT01299480; NCT000808028; NCT00879814; NCT00780806; NCT01352845; NCT01352793; NCT01461993; NCT01323270; NCT01830855; NCT01461980; NCT01768117.

MenB-FHbp Vaccine Protects Against Diverse Meningococcal Strains in Adolescents and Young Adults: Post Hoc Analysis of Two Phase 3 Studies

Introduction

Two phase 3 studies in adolescents and young adults demonstrated that MenB-FHbp, a meningococcal serogroup B (MenB) vaccine, elicits protective immune responses after 2 or 3 doses based on serum bactericidal antibody assays using human complement (hSBA) against 4 primary and 10 additional diverse, vaccine-heterologous MenB test strains. Lower limits of quantitation (LLOQs; titers 1:8 or 1:16; titers ≥ 1:4 correlate with protection) were used to evaluate responses to individual strains and all 4 primary strains combined (composite response). A post hoc analysis evaluated percentages of subjects with protective responses to as many as 8 strains combined (4 primary plus additional strains).

Methods

Immune responses were measured using hSBAs against 4 primary strains in adolescents (n = 1509, MenB-FHbp; n = 898, hepatitis A virus vaccine/saline) and young adults (n = 2480, MenB-FHbp; n = 824, saline) receiving MenB-FHbp or control at 0, 2, and 6 months. Ten additional strains were evaluated in subsets of subjects from approximately 1800 MenB-FHbp recipients across both studies. Percentages of subjects with hSBA titers ≥ LLOQ for different numbers of primary strains or primary plus additional strains combined (7 or 8 strains total per subset) were determined before vaccination, 1 month post-dose 2, and 1 month post-dose 3.

Results

Across the panel of primary plus additional strains, at 1 month post-dose 3, titers ≥ LLOQ were elicited in 93.7–95.7% of adolescents and 91.7–95.0% of young adults for ≥ 5 test strains combined and in 70.5–85.8% of adolescents and 67.5–81.4% of young adults for ≥ 7 strains combined. Among adolescents, 99.8%, 99.0%, 92.8%, and 82.7% had titers ≥ LLOQ against at least 1, 2, 3, and all 4 primary strains, respectively; corresponding percentages for young adults were 99.7%, 97.7%, 94.0%, and 84.5%.

Conclusions

Results support the ability of MenB-FHbp to provide broad coverage against MenB strains expressing diverse FHbp variants.

Trial Registration

ClinicalTrials.gov identifiers NCT01830855, NCT01352845.

Electronic supplementary material

The online version of this article (10.1007/s40121-020-00319-0) contains supplementary material, which is available to authorized users.

Persistence and 4-year boosting of the bactericidal response elicited by two- and three-dose schedules of MenB-FHbp: A phase 3 extension study in adolescents

BACKGROUND

The period of heightened risk of invasive meningococcal disease in adolescence extends for >10 years. This study aimed to evaluate persistence of the immune response to the serogroup B meningococcal (MenB) vaccine MenB-FHbp (Trumenba^®, Bivalent rLP2086) under two- and three-dose primary vaccination schedules, both of which are approved in the United States and the European Union, and to assess safety and immunogenicity of a booster dose.

METHODS

This was an open-label extension study of a phase 2 randomized MenB-FHbp study (primary study). This interim analysis includes data through 1 month after booster vaccination. In the primary study, adolescents 11-18 years of age were randomized using an interactive voice or web-based response system to receive 120 μg MenB-FHbp under 0-, 1-, 6-month; 0-, 2-, 6-month; 0-, 6-month; 0-, 2-month; or 0-, 4-month schedules (termed study groups for the current analysis). For the primary study, participants were blinded to their vaccine study group allocation, but investigators and the study sponsor were unblinded. Immune responses in subjects from the primary study were evaluated through 48 months after primary vaccination (persistence stage; 17 sites in Czech Republic, Denmark, Germany, and Sweden). Safety and immunogenicity of a booster dose given at 48 months after primary vaccination (booster stage; 14 sites in Czech Republic, Denmark, and Sweden) were also assessed. Immune responses were evaluated in serum bactericidal assays with human complement (hSBAs) using four MenB test strains representative of disease-causing MenB strains in the United States and Europe and expressing factor H binding proteins (FHbps) heterologous to the vaccine antigens. The primary immunogenicity endpoints were the proportions of subjects with hSBA titers greater than or equal to the assays' lower limit of quantitation (LLOQ; 1:8 or 1:16 depending on strain) at 12, 18, 24, 36, and 48 months after primary vaccination (persistence stage) and 1 and 48 months after the primary vaccination series and 1 month after receipt of the booster dose (booster stage). Safety evaluations during the booster stage included local reactions and systemic events by severity, antipyretic use, adverse events (AEs), immediate AEs, serious AEs (SAEs), medically attended AEs (MAEs), newly diagnosed chronic medical conditions (NDCMCs), and missed days of school and work because of AEs. The modified intent-to-treat (mITT) population was used for immunogenicity evaluations in the persistence stage. The booster stage immunogenicity evaluations used the evaluable immunogenicity population; analyses were also performed in the mITT population. For the persistence stage, safety evaluations included subjects with at least one blood draw, whereas for the booster stage, they included subjects who received the booster dose and had available safety data. This trial is registered at ClinicalTrials.gov number NCT01543087.

FINDINGS

A total of 465 subjects were enrolled in the persistence stage, and 271 subjects were enrolled in the booster stage. Sera for the extension phase of this interim analysis were collected from September 7, 2012 to December 7, 2015. One month after primary vaccination, 73.8-100.0% of subjects depending on study group responded with hSBA titers ≥LLOQ. Response rates declined during the 12 months after last primary vaccination and then remained stable through 48 months, with 18.0-61.3% of subjects depending on study group having hSBA titers ≥LLOQ at this time point. One month after receipt of the booster dose, 91.9-100.0% of subjects depending on study group had hSBA titers ≥LLOQ against the four primary strains individually and 91.8-98.2% had hSBA titers ≥LLOQ against all four strains combined (composite response). Geometric mean titers were higher after booster vaccination than at 1 month after primary vaccination. Immune responses were generally similar across study groups, regardless of whether a two- or three-dose primary series was received. None of the AEs (2.2-6.9% of subjects depending on study group) or NDCMCs (1.8-5.0%) that were reported during the persistence stage were considered related to the investigational product. Local reactions and systemic events were reported by 84.4-93.8% and 68.8-76.6% of subjects depending on study group, respectively, in the booster stage; these were generally similar across study groups, transient, and less frequent than after any primary vaccination. Additionally, there was no general progressive worsening in severity of reactogenicity events (ie, potentiation; ≤3 subjects per group), and reactogenicity events did not lead to any study withdrawals. No NDCMCs or immediate AEs were reported during the booster stage. AEs were reported by 3.7-12.5% of subjects depending on study group during the booster stage. The two possibly related AEs included a mild worsening of psoriasis and a severe influenza-like illness that resolved in 10 days.

INTERPRETATION

Immune responses declined after the primary vaccination series; however, a substantially greater number of subjects retained protective responses at 48 months after primary vaccination compared with subjects having protective responses before vaccination. Persistence trends were similar across all 5 study groups regardless of whether a two- or three-dose primary schedule was received. Furthermore, a booster dose given 48 months after primary vaccination was safe, well-tolerated, and elicited robust immune responses indicative of immunologic memory; these responses were similar between two- and three-dose primary schedule study groups. Use of a booster dose may help further extend protection against MenB disease in adolescents.

FUNDING

Pfizer Inc.

A Bivalent Meningococcal B Vaccine in Adolescents and Young Adults

BACKGROUND

MenB-FHbp is a licensed meningococcal B vaccine targeting factor H-binding protein. Two phase 3 studies assessed the safety of the vaccine and its immunogenicity against diverse strains of group B meningococcus.

METHODS

We randomly assigned 3596 adolescents (10 to 18 years of age) to receive MenB-FHbp or hepatitis A virus vaccine and saline and assigned 3304 young adults (18 to 25 years of age) to receive MenB-FHbp or saline at baseline, 2 months, and 6 months. Immunogenicity was assessed in serum bactericidal assays that included human complement (hSBAs). We used 14 meningococcal B test strains that expressed vaccine-heterologous factor H-binding proteins representative of meningococcal B epidemiologic diversity; an hSBA titer of at least 1:4 is the accepted correlate of protection. The five primary end points were the proportion of participants who had an increase in their hSBA titer for each of 4 primary strains by a factor of 4 or more and the proportion of those who had an hSBA titer at least as high as the lower limit of quantitation (1:8 or 1:16) for all 4 strains combined after dose 3. We also assessed the hSBA responses to the primary strains after dose 2; hSBA responses to the 10 additional strains after doses 2 and 3 were assessed in a subgroup of participants only. Safety was assessed in participants who received at least one dose.

RESULTS

In the modified intention-to-treat population, the percentage of adolescents who had an increase in the hSBA titer by a factor of 4 or more against each primary strain ranged from 56.0 to 85.3% after dose 2 and from 78.8 to 90.2% after dose 3; the percentages of young adults ranged from 54.6 to 85.6% and 78.9 to 89.7%, after doses 2 and 3, respectively. Composite responses after doses 2 and 3 in adolescents were 53.7% and 82.7%, respectively, and those in young adults were 63.3% and 84.5%, respectively. Responses to the 4 primary strains were predictive of responses to the 10 additional strains. Most of those who received MenB-FHbp reported mild or moderate pain at the vaccination site.

CONCLUSIONS

MenB-FHbp elicited bactericidal responses against diverse meningococcal B strains after doses 2 and 3 and was associated with more reactions at the injection site than the hepatitis A virus vaccine and saline. (Funded by Pfizer; ClinicalTrials.gov numbers, NCT01830855 and NCT01352845 ).

Meningococcal serogroup B vaccines: Estimating breadth of coverage

Neisseria meningitidis serogroup B (MenB) is an important cause of invasive meningococcal disease. The development of safe and effective vaccines with activity across the diversity of MenB strains has been challenging. While capsular polysaccharide conjugate vaccines have been highly successful in the prevention of disease due to meningococcal serogroups A, C, W, and Y, this approach has not been possible for MenB owing to the poor immunogenicity of the MenB capsular polysaccharide. Vaccines based on outer membrane vesicles have been successful in the prevention of invasive MenB disease caused by the single epidemic strain from which they were derived, but they do not confer broad protection against diverse MenB strains. Thus, alternative approaches to vaccine development have been pursued to identify vaccine antigens that can provide broad protection against the epidemiologic and antigenic diversity of invasive MenB strains. Human factor H binding protein (fHBP) was found to be such an antigen, as it is expressed on nearly all invasive disease strains of MenB and can induce bactericidal responses against diverse MenB strains. A bivalent vaccine (Trumenba®, MenB-FHbp, bivalent rLP2086) composed of equal amounts of 2 fHBP variants from each of the 2 immunologically diverse subfamilies of fHBP (subfamilies A and B) was the first MenB vaccine licensed in the United States under an accelerated approval pathway for prevention of invasive MenB disease. Due to the relatively low incidence of meningococcal disease, demonstration of vaccine efficacy for the purposes of licensure of bivalent rLP2086 was based on vaccine-elicited bactericidal activity as a surrogate marker of efficacy, as measured in vitro by the serum bactericidal assay using human complement. Because bacterial surface proteins such as fHBP are antigenically variable, an important component for evaluation and licensure of bivalent rLP2086 included stringent criteria for assessment of breadth of coverage across antigenically diverse and epidemiologically important MenB strains. This review describes the rigorous approach used to assess broad coverage of bivalent rLP2086. Alternative nonfunctional assays proposed for assessing vaccine coverage are also discussed.

Local induction of a specific Th1 immune response by allergen linked immunostimulatory DNA in the nasal explants of ragweed-allergic subjects

BACKGROUND

Allergen immunotherapy is effective in allergic individuals however efforts are being made to improve its safety, convenience, and efficacy. It has recently been demonstrated that allergen-linked immunostimulatory DNA (ISS) is effective in stimulating an allergen-specific Th1 response with decreased allergenicity. The objective of this study is to investigate whether ISS linked to purified ragweed allergen Amb-a-1 (AIC) can inhibit local allergen-specific Th2 and induce allergen-specific Th1 responses in explanted nasal mucosa of ragweed-sensitive subjects. In addition, we set out to determine whether AIC is more effective compared to stimulation with unlinked Amb a 1 and ISS.

METHODS

Tissue from ragweed-sensitive patients (n = 12) was cultured with whole ragweed allergen (RW), Amb-a-1, AIC, Amb-a-1 and ISS (unlinked), or tetanus toxoid (TT) for 24 hours. IL-4, -5, -13, TNF-alpha and IFN-gamma mRNA-positive cells were visualized by in situ hybridization and T cells, B cells and neutrophils were enumerated using immunocytochemistry.

RESULTS

RW or Amb-a-1 increased the number of IL-4, IL-5, and IL-13 mRNA+ cells in the tissue compared to medium alone. AIC had similar cytokine mRNA reactivity as control tissue. AIC and TT increased IFNgamma-mRNA expression. Unlinked Amb-a-1 and ISS showed similar effects to AIC, however this response was weaker. The number of TNF mRNA+ cells, T cells, B cells and neutrophils remained unchanged.

CONCLUSIONS

AIC is effective in stimulating a local allergen-specific Th1- and abolishing Th2-cytokine mRNA reactivity in the nose and may be considered as a strong candidate for an improved approach to immunotherapy in ragweed-sensitive individuals.

Immunotherapy with a ragweed-toll-like receptor 9 agonist vaccine for allergic rhinitis

BACKGROUND

Conjugating immunostimulatory sequences of DNA to specific allergens offers a new approach to allergen immunotherapy that reduces acute allergic responses.

METHODS

We conducted a randomized, double-blind, placebo-controlled phase 2 trial of a vaccine consisting of Amb a 1, a ragweed-pollen antigen, conjugated to a phosphorothioate oligodeoxyribonucleotide immunostimulatory sequence of DNA (AIC) in 25 adults who were allergic to ragweed. Patients received six weekly injections of the AIC or placebo vaccine before the first ragweed season and were monitored during the next two ragweed seasons.

RESULTS

There was no pattern of vaccine-associated systemic reactions or clinically significant laboratory abnormalities. AIC did not alter the primary end point, the vascular permeability response (measured by the albumin level in nasal-lavage fluid) to nasal provocation. During the first ragweed season, the AIC group had better peak-season rhinitis scores on the visual-analogue scale (P=0.006), peak-season daily nasal symptom diary scores (P=0.02), and midseason overall quality-of-life scores (P=0.05) than the placebo group. AIC induced a transient increase in Amb a 1-specific IgG antibody but suppressed the seasonal increase in Amb a 1-specific IgE antibody. A reduction in the number of interleukin-4-positive basophils in AIC-treated patients correlated with lower rhinitis visual-analogue scores (r=0.49, P=0.03). Clinical benefits of AIC were again observed in the subsequent ragweed season, with improvements over placebo in peak-season rhinitis visual-analogue scores (P=0.02) and peak-season daily nasal symptom diary scores (P=0.02). The seasonal specific IgE antibody response was again suppressed, with no significant change in IgE antibody titer during the ragweed season (P=0.19).

CONCLUSIONS

In this pilot study, a 6-week regimen of the AIC vaccine appeared to offer long-term clinical efficacy in the treatment of ragweed allergic rhinitis. (ClinicalTrials.gov number, NCT00346086 [ClinicalTrials.gov] .).

Comparison of the safety and immunogenicity of hepatitis B virus surface antigen co-administered with an immunostimulatory phosphorothioate oligonucleotide and a licensed hepatitis B vaccine in healthy young adults

BACKGROUND

Many individuals do not respond to a three-dose series of hepatitis B vaccine (HBV) and most do not achieve a protective antibody response until after dose 2 or 3.

METHODS

Healthy, seronegative 18-28 year old adults were randomly assigned in equal numbers to receive two doses of the experimental vaccine (HBV-ISS without alum) (0, 8 weeks) and placebo (24 weeks) or Engerix-B (0, 8, 24 weeks). Adverse events were collected during the first week and at 4 weeks after each injection. Antibodies were measured 4 weeks after dose 1; before, 1 and 4 weeks after dose 2, and before, 1 and 4 weeks after dose 3 and at 1 year.

RESULTS

Ninety-nine participants were enrolled (65% female; mean age 22.6 years). 79% of HBV-ISS and 12% of Engerix-B recipients had a protective antibody response 4 weeks post dose 1 (geometric mean concentration [GMC] 23.0 and 1.87 mIU/mL, respectively). By 1 week post dose 2, 100% of HBV-ISS and 18% Engerix-B recipients had protective levels (GMC 1603 versus 2.40 mIU/mL). Rates of adverse events were low and similar in both groups; headache and fatigue were the most common systemic adverse events in up to 1/3 of both groups. Mild injection-site tenderness was more common after HBV-ISS than Engerix-B after both doses (74-77% compared to 34-58%; p<or=0.029).

CONCLUSIONS

Protective levels are achieved more quickly and after fewer doses of HBV-ISS than Engerix-B. HBV-ISS is well tolerated but associated with more mild injection-site tenderness than Engerix-B.

Selective immune redirection in humans with ragweed allergy by injecting Amb a 1 linked to immunostimulatory DNA

BACKGROUND

In animal models administration of immunostimulatory DNA sequences preferentially elicits T(H)1-dominated (type 1-dominated) immunity and can inhibit developing or ongoing T(H)2 (type 2) responses.

OBJECTIVE

Our objective was to investigate this phenomenon in humans.

METHODS

In a randomized, third party-blinded, placebo-controlled, proof-of-concept study conducted entirely in the winter in 19 adults with ragweed allergy, we administered 6 subcutaneous injections of purified Amb a 1 linked to the 22-base-long immunostimulatory phosphorothioate oligodeoxyribonucleotide 1018 (Amb a 1-immunostimulatory DNA sequence conjugate [AIC]). Before the course of AIC or placebo injections and 2 and 16 weeks afterward, we measured recall responses to ragweed, streptokinase, and PHA in short-term primary culture of fresh PBMCs after restimulation with antigen. We quantified regulatory cytokine and chemokine responses characteristic of T(H)2 immunity (IL-5, IL-13, CCL17 [TARC], and CCL22 [MDC]), and T(H)1 immunity (IFN-gamma, CXCL9 [Mig], and CXCL10 [IP-10]), as well as IL-10, a cytokine sometimes linked to regulatory T-cell populations.

RESULTS

We demonstrated for the first time that human systemic in vivo ragweed-specific T(H)2 responses were selectively redirected toward T(H)1 responses, with significant increases in IFN-gamma, CXCL9, and CXCL10 and significant decreases in IL-5, CCL17, and CCL22 found at 2 and 16 weeks after the sixth injection. Cytokine and chemokine responses to the unrelated bacterial antigen streptokinase and the global capacity to mount immune responses on polyclonal activation with PHA did not change. No clinically significant systemic or local allergic reactions were associated with AIC or placebo injections.

CONCLUSIONS

AIC, injected in concentrations that were approximately 40-fold lower than those used in most murine studies published to date, led to a prolonged shift from T(H)2 immunity toward T(H)1 immunity and appeared to be safe. This novel approach has the potential for immune redirection in human immediate hypersensitivity diseases.

Rotavirus immunoglobulin a responses stimulated by each of 3 doses of a quadrivalent human/bovine reassortant rotavirus vaccine

A quadrivalent precursor to the pentavalent rotavirus vaccine candidate RotaTeq was evaluated in a 3-dose, 439-subject study. To determine immunogenicity, the quantity of rotavirus immunoglobulin A (IgA) in stool specimens obtained, at 1 of 10 study sites, from 37 placebo and 37 vaccine recipients was measured. None of the placebo recipients showed a clinically important (>/=3-fold) increase in stool rotavirus IgA, whereas 31 vaccine recipients showed an increase after at least 1 dose of vaccine. In total, 16, 19, and 15 vaccine recipients had increases after 1, 2, and 3 doses, respectively, indicating that a 3-dose regimen increased the immune response elicited by this vaccine.

Infant immune response to human rotavirus serotype G1 vaccine candidate reassortant WI79-9: different dose response patterns to virus surface proteins VP7 and VP4

BACKGROUND

Rotavirus is the leading cause of morbidity from gastroenteritis in the developed world and the leading cause of mortality from viral gastroenteritis (estimated 600000 deaths) worldwide. G1 is the most prevalent human serotype. Reassortant rotavirus between simian rotavirus RRV or bovine rotavirus WC3 and human strain rotaviruses have been extensively tested as candidate vaccines. Rotavirus (RV) reassortant strain WI79-9 consists of a human (strain WI79) G1 serotype VP7 surface protein on a bovine (strain WC3) background. It is a key component of a pentavalent (G1, G2, G3, G4 and P1) WC3 reassortant vaccine candidate, RotaTeq, now being tested in Phase III clinical trials.

METHODS

We studied 84 infants between the ages of 2 and 8 months who received 3 oral doses of WI79-9. Serum neutralizing antibody was measured to the human (WI79 serotype P1 G1) and bovine (WC3 serotype P7 G6) parent RV after each dose. A significant response was defined as a > or =3-fold rise in antibody titer between the predose and postdose sera.

RESULTS

In two separate cohorts of vaccinees given three doses of WI79-9 reassortant rotavirus, 68 to 75% of infants demonstrated a significant response to WC3 (VP4, P7) after Dose 1, fewer (24 to 39%) responses were detected after Dose 2 and rare (0 to 4%) additional responses occurred after Dose 3. The cumulative response rate to WC3 after three doses was 95% in both trials. In contrast 23 to 37% had a significant response to WI79 (VP7, G1) after Dose 1, and 57 to 61% had a significant response after Dose 2. Additional significant responses after Dose 3 led to a cumulative response of 70 to 84%.

CONCLUSION

Two doses of G1 reassortant WI79 were necessary to induce significant antibody responses to human G1 (VP7) antigen in >50% of infants. Three doses were required to achieve significant antibody responses to VP7 in >70% of infants.

Safety, efficacy, and immunogenicity of a live, quadrivalent human-bovine reassortant rotavirus vaccine in healthy infants

OBJECTIVES

To investigate safety, efficacy, and immunogenicity of live quadrivalent rotavirus vaccine (QRV) containing human-bovine (WC3) reassortant rotavirus serotypes G1, G2, G3, and P1a.

STUDY DESIGN

This was a randomized, double-blinded, placebo-controlled trial. During 1993 to 1994, at 10 US study sites, 439 healthy infants approximately 2 to 6 months of age, were enrolled to receive 3 doses of oral QRV or placebo at approximately 8-week intervals.

RESULTS

The vaccine was generally well tolerated; no serious vaccine-related adverse experiences were reported. Risk differences and 95% confidence intervals suggested no differences between vaccine and placebo recipients in the incidences of fever, irritability, vomiting, or diarrhea during the 14 days after any dose. QRV was 74.6% efficacious (95% CI: 49.5%, 88.3%) in preventing rotavirus acute gastroenteritis (AGE), regardless of severity and 100% efficacious (95% CI: 43.5%, 100%) in preventing severe rotavirus AGE through one rotavirus season. Serotype G1 was identified in most infants with rotavirus AGE. A >or=3-fold rise in serum neutralizing antibody to G1 was observed in 57% (45/79) of vaccinees. A >or=3-fold rise in serum anti-rotavirus IgA and fecal anti-rotavirus IgA was observed in 88% (162/185) and 65% (104/159) of vaccinees, respectively.

CONCLUSIONS

QRV was generally well tolerated, immungenic, and highly effective against rotavirus gastroenteritis.

A phase I study of the safety and immunogenicity of recombinant hepatitis B surface antigen co-administered with an immunostimulatory phosphorothioate oligonucleotide adjuvant

Certain oligodeoxynuclotides with CpG motifs provide enhanced immune response to co-delivered antigens. We performed a phase I, observer-blinded, randomized study in healthy anti-hepatitis B surface antigen (anti-HBsAg) antibody negative adults to explore safety and immunogenicity of co-injection of recombinant HBsAg combined with an immunostimulatory DNA sequence (ISS) 1018 ISS. Four ISS dosage groups (N=12 per group) were used: 300, 650, 1000 or 3000 microg. For each group, two controls received 20 microg HBsAg alone, two controls received ISS alone, and eight subjects received ISS+20 microg HBsAg. Subjects received two doses 8 weeks apart. Injection site reactions (tenderness and pain on limb movement) were more frequent at higher ISS+HBsAg doses but were mainly mild and of short duration. Higher anti-HBsAg antibody levels were associated with higher ISS doses. Four weeks after the first dose, a seroprotective titer (>or=10 mIU/ml) was noted for 0, 25, 75, and 87.5% of subjects by increasing ISS dose group (P<0.05) for those who received ISS+HBsAg; 1 month after the second dose this increased to 62.5, 100, 100, and 100%, respectively. Geometric mean anti-HBsAg antibody levels by increasing ISS+HBsAg dose were 1.22, 5.78, 24.75, and 206.5 mIU/ml after the first dose and 65.37, 877.6, 1545, and 3045 mIU/ml after the second dose. We conclude that 1018 ISS+HBsAg was well tolerated and immunogenic in this phase I study in healthy adults and may offer the potential for enhancement of hepatitis B virus (HBV) immunization and protection after one or two doses or in individuals who fail to respond to the standard vaccine regimen.

Immunostimulatory sequence DNA linked to the Amb a 1 allergen promotes T(H)1 cytokine expression while downregulating T(H)2 cytokine expression in PBMCs from human patients with ragweed allergy

BACKGROUND

Recent studies have demonstrated that bacterially derived immunostimulatory sequences (ISSs) of DNA can activate the mammalian innate immune system and promote the development of T(H)1 cells. Promotion of T(H)1 immunity by means of immunotherapy in allergic patients has led to the alleviation of symptoms that result from allergen-specific T(H)2 responses.

OBJECTIVE

Our purpose was to investigate whether the T(H)1-enhancing properties of ISSs could be used to alter the T(H)2-dominated immune response of allergic PBMCs in vitro.

METHODS

Ragweed protein-linked ISS (PLI) was generated from a specific, highly active 22-base ISS and Amb a 1, the immunodominant allergen in ragweed pollen, to combine the T(H)1-enhancing properties of ISSs with allergen selectivity, and its activity was investigated in PBMC cultures from subjects with ragweed allergy.

RESULTS

PLI was markedly successful at reversing the dominant allergen-induced T(H)2 profile while greatly enhancing IFN-gamma production. Delivering ISSs in a linked form proved to be much more effective at modulating the resulting cytokine profile than delivering free ISSs in a mixture with unlinked Amb a 1. PLI also demonstrated cytokine-modulating properties, even when used to stimulate cells that had already been primed for 6 days with Amb a 1. The antigen specificity of the action of PLI was confirmed by the observations that PLI enhances Amb a 1--specific T-cell proliferation.

CONCLUSION

These data indicate that delivery of ISSs within an antigen-specific context exhibits potent cytokine-modulating activity and, combined with its reduced allergenicity, makes this molecule a strong candidate for use in improved immunotherapy applications.

Conjugation of immunostimulatory DNA to the short ragweed allergen amb a 1 enhances its immunogenicity and reduces its allergenicity

BACKGROUND

Allergen immunotherapy is inconvenient and associated with the risk of anaphylaxis. Efforts to improve the safety of immunotherapy by means of chemical modification of allergens have not been successful because it greatly reduced their antigenicity. Recently, immunostimulatory DNA sequences (ISS or CpG motifs) have been shown to act as strong T(H)1 response-inducing adjuvants.

OBJECTIVE

We sought to determine whether conjugation of ISS to the major short ragweed allergen Amb a 1 results in enhanced immunotherapeutic potential in mice and decreased allergenicity in human subjects.

METHODS

A 22-mer ISS oligodeoxynucleotide (ISS-ODN) was coupled to Amb a 1 and used for immunization of mice, rabbits, and monkeys.

RESULTS

In mice the Amb a 1-ISS conjugate induced a T(H)1 response (IFN-gamma secretion), whereas Amb a 1 induced a T(H)2 response (IL-5 secretion). The T(H)1 response was not observed with an Amb a 1-non-ISS conjugate. Coinjection of Amb a 1 with ISS-ODN was much less effective in inducing a T(H)1 response. In mice primed for a T(H)2 response, injection with Amb a 1-ISS conjugate induced a de novo T(H)1 response and suppressed IgE antibody formation after challenge with Amb a 1. Amb a 1-ISS conjugate induced high-titer anti-Amb a 1 IgG antibodies in rabbits and cynomolgus monkeys, whereas Amb a 1 alone or Amb a 1 coinjected with ISS-ODN did not induce a detectable response. Amb a 1-ISS conjugate was less allergenic than Amb a 1 alone, as shown by a 30-fold lower histamine release from human basophils of patients with ragweed allergy, whereas mixing ISS-ODN with Amb a 1 did not reduce histamine release.

CONCLUSION

Amb a 1-ISS conjugate has an enhanced T(H)1-biased immunogenicity and reduced allergenicity. It may offer a more effective and safer approach for allergen immunotherapy than currently available methods.

Conjugation of protein to immunostimulatory DNA results in a rapid, long-lasting and potent induction of cell-mediated and humoral immunity

Immunostimulatory DNA sequences (ISS) are a potent Th1 adjuvant. We hypothesized that conjugation of ISS to protein antigens would strongly enhance their immunogenicity because both antigen and adjuvant (ISS) would be delivered to the same locale/antigen-presenting cell. To test this hypothesis, we conjugated a 22-mer immunostimulatory oligodeoxynucleotide (ISS-ODN) to two test antigens of differing intrinsic immunogenicity, namely Escherichia coli beta-galactosidase and the HIV-1 envelope glycoprotein gp120. We show that the antigen-ISS conjugates rapidly induce Th1 cells secreting high levels of IFN-gamma, strong CTL activity, and high titer IgG2a and HIV-neutralizing antibodies, exceeding gene and protein vaccination alone or immunization with mixtures of antigen and ISS-ODN. The data suggest that this procedure generates a novel and unique vaccine that rapidly triggers strong humoral and cell-mediated immunity.

The development of multivalent bovine rotavirus (strain WC3) reassortant vaccine for infants

Laboratory and clinical studies have been directed toward development of a vaccine against rotavirus gastroenteritis in infants. First, bovine rotavirus strain WC3, which did not induce neutralizing antibodies to predominant human rotavirus (HRV) serotypes, was determined to be safe and immunogenic; however, it was not protective in all efficacy trials. HRVs adapted to cell culture retained some virulence for infants, but when further attenuated by cold adaptation, they were poorly immunogenic. Reassortant rotaviruses were designed to express HRV surface proteins VP7 (G) or VP4 (P) while retaining a bovine WC3 genome background. Reassortants containing either HRV surface protein and as few as four bovine rotavirus genes were safe in infants. A monovalent WC3 reassortant of serotype G1 specificity was 64%-100% protective in placebo-controlled trials. A quadrivalent WC3 reassortant vaccine with components of HRV G1, G2, G3, and P[8] specificity induced 67% protection against all rotavirus disease in a multicenter efficacy trial.

Rescue of immunoglobulins from insolubility is facilitated by PDI in the baculovirus expression system

A substantial fraction of immunoglobulin heavy and light chain polypeptides were insoluble when expressed in the baculovirus-insect cell expression system. In the presence of coexpressed heterologous protein disulfide isomerase (PDI), however, the solubility of the immunoglobulins was enhanced and IgG was secreted at higher levels from baculovirus-infected Trichoplusia ni insect cells. Pulse-chase experiments indicated that some immunoglobulin polypeptides were initially insoluble in the presence of PDI but subsequently were rescued in a soluble form competent for IgG assembly and secretion. Recovery of the insoluble immunoglobulins was not observed in the absence of coexpressed PDI. Even after treatment of insect cells with tunicamycin to inhibit N-glycosylation of immunoglobulin heavy chains, coexpressed PDI was able to salvage insoluble immunoglobulins and secrete these modified glycoforms. The capacity for PDI to rescue immunoglobulins was also demonstrated in vitro where immunoglobulin heavy chains and light chain dimers were salvaged from aggregates of denatured IgG. PDI-mediated rescue of proteins, perhaps assisted by chaperones and other foldases, may be important in vivo where insolubility is a common occurrence for newly synthesized polypeptides.

WC3 reassortant vaccines in children

Bovine rotavirus strain WC3 (P7[5], G6) administered at the 12th passage level was well tolerated clinically in infants and efficiently induced serum virus neutralizing antibody (VNA) with bovine rotavirus G6 specificity. The protective efficacy of WC3 vaccine against all rotavirus disease was inconsistent, varying in four separate trials from 76% to 0%; some selective protection against severe disease was seen in all trials. WC3 reassortants containing the gene for an individual human rotavirus VP7 (G) or VP4 (P) surface antigen were also well tolerated, but preferentially induced VNA to the WC3 parent. Efficacy trials of human G1 VP7 reassortant WI79-9 (P7[5], G1) consistently led to > 60% protection against all rotavirus disease. A quadrivalent WC3 reassortant vaccine was developed to contain four separate monovalent reassortants expressing human rotaviruses surface proteins G1, G2, G3, and P1A [8] respectively. In a multicenter trial including 439 infants, this vaccine induced 67.1% protection against all rotavirus disease (defined as positive for rotavirus antigen by ELISA only [p = < 0.001]) and 72.6% protection when the standard for rotavirus diagnosis was a positive test of stool for both rotavirus antigen by ELISA and rotavirus RNA by electropherotype analysis (p = < 0.001). In this trial, episodes of the most severe rotavirus disease (clinical severity score > 16.0 eight cases) occurred only in placebo recipients.

Hematologic consequences of Borna disease virus infection of rat bone marrow and thymus stromal cells

Borna disease virus (BDV) was previously believed to have a strict tropism for the nervous system. BDV has recently been identified by a reverse transcription-polymerization chain reaction-enzyme immunosorbent assay (RT-PCR-EIA) in bone marrow cells and peripheral blood mononuclear cells (PBMC) in BDV-infected Lewis rats. We now report the identification of BDV RNA and infectious virus in thymus cells from rats infected either as neonates (PTI-NB) or as adults (4 weeks of age). Based on in vitro studies, we determined that the BDV-infected cells in bone marrow and thymus tissue are fibroblastic stromal cells. Bone marrow stromal cells are nonhematopoietic, fixed-tissue elements that support hematopoiesis, and, thus, it was not surprising that BDV infection altered the recovery from granulocytopenia and leukocytopenia after myelosuppressive treatment. Notably, unlike other immunotropic and neurotropic viruses, BDV does not appear to infect cells of myeloid or lymphoid lineages. We also report the association between BDV in the thymus with the lack, or loss, of encephalitis in neonatally inoculated rats or adult-inoculated rats during the chronic stage of disease.

Effects of co-expressing chaperone BiP on functional antibody production in the baculovirus system

The assembly pathway of the insect cell Spodoptera frugiperda (Sf-9) was engineered to include expression of the murine chaperone immunoglobulin heavy chain binding protein (BiP) using the baculovirus vector. The impact of BiP coexpression on the production and secretion of functional and soluble recombinant immunoglobulin IgG levels was evaluated. Recombinant BiP was found to associate specifically with immunoglobulins in immunoprecipitation studies. Coinfection of insect cells with a BiP-containing baculovirus and baculoviruses coding for two different murine IgG proteins increased intracellular functional antibody activity levels substantially above the levels observed in the absence of BiP. Soluble intracellular immunoglobulin levels were found to increase as well. However, secreted functional antibody levels did not increase significantly. Also, degradation of heavy chain immunoglobulin in insect cells was indicated by the accumulation of lower molecular weight immunoglobulins at 4 days postinfection. Coexpression of light chains reduced the level of these lower molecular weight immunoglobulins while BiP coexpression led to enhanced levels. These findings suggest that coexpressed BiP can increase intracellular soluble and functional antibody yields but that secretion in the baculovirus-insect cell system must be limited at some post-translational step.

Borna disease virus p24 and p38/40 synthesized in a baculovirus expression system: virus protein interactions in insect and mammalian cells

To facilitate studies of the individual viral proteins, two Borna disease virus proteins, p24 and p38/40, were synthesized in vitro by means of a baculovirus expression system and examined for antigenic identity to viral proteins from BDV-infected cells. Recombinant proteins p24 and p38/40 were nearly identical in size to the viral proteins from BDV-infected cells. Immunoblot and immunocytochemistry analysis of BDV proteins from infected tissue culture cells and rat brain showed binding of antisera directed against the recombinant proteins. Specific recognition of the recombinant proteins by Borna disease virus-specific convalescent antisera and monoclonal antibodies further demonstrated that the antigenic characters of the p24 and p38/40 had been conserved. Polyclonal antibody directed against either of the recombinant proteins recognized only the protein used as immunogen, without cross reactivity with the other recombinant protein, indicating no common epitopes. Moreover, these data confirmed the proposed gene coding assignments of ORF I and II of BDV p38/40 and p24, respectively. Both of the recombinant proteins were secreted into the media of insect cells in tissue culture, but secretion of recombinant p24 was evident only as a dimeric form and not with the monomeric form. Immunoprecipitation studies performed with monoclonal antibodies and BDV proteins from infected rat brain suggested that a heterodimer forms via binding of p40 to the p24.

Diagnosis of Chlamydia pneumoniae infection in patients with community-acquired pneumonia by polymerase chain reaction enzyme immunoassay

We conducted a prospective study of 385 patients who had community-acquired pneumonia with use of a modified polymerase chain reaction (PCR) assay that detects amplified DNA by enzyme immunoassay (EIA). We used PCR-EIA to improve detection of Chlamydia pneumoniae infection and to differentiate C. pneumoniae infection from other chlamydial infections. Cultures of throat swab specimens from four patients yielded Chlamydia species (C. pneumoniae, one patient; Chlamydia species, two patients; and C. psittaci, one patient). C. pneumoniae was repeatedly detected by PCR-EIA for thirteen (3.4%) of these 385 patients. Six of these 13 patients were infected with the human immunodeficiency virus. Ten (76.9%) of the patients who were positive by PCR-EIA had IgG titers of > or = 1:16, and two (15.4%) of the 13 patients had IgG titers of < 1:16; no sera was available in one case. Other pathogens were recovered in eight (61.5%) of the 13 cases in which C. pneumoniae was detected by PCR-EIA. In addition, for 46 (11.9%) of the 385 patients the titers of antibody were considered diagnostic of C. pneumoniae infection; however, as 36 of the 46 patients were infected with the human immunodeficiency virus (which may have affected their serological response to C. pneumoniae), interpretation of these titers was problematic. As PCR-EIA was more sensitive than was culture for detecting C. pneumoniae infection in this study, this method may be a valuable tool for the prompt diagnosis of this infection.

Enteric infectious disease in neonates. Epidemiology, pathogenesis, and a practical approach to evaluation and therapy

There are many bacterial and viral pathogens that have been associated with enteric disease during the newborn period. These pathogens have widely different mechanisms of action on the intestinal epithelium and are associated with a spectrum of clinical findings. Infected infants can be asymptomatic, have gastroenteritis, or have a fulminant sepsis picture. To determine therapy and institute appropriate infection control measures requires the ability to recognize the clinical syndrome and correctly interpret laboratory results. All of these principles can be applied to the premature infant in the neonatal intensive care nursery as well as the full-term infant at home.

Enteric infectious disease in neonates. Epidemiology, pathogenesis, and a practical approach to evaluation and therapy

There are many bacterial and viral pathogens that have been associated with enteric disease during the newborn period. These pathogens have widely different mechanisms of action on the intestinal epithelium and are associated with a spectrum of clinical findings. Infected infants can be asymptomatic, have gastroenteritis, or have a fulminant sepsis picture. To determine therapy and institute appropriate infection control measures requires the ability to recognize the clinical syndrome and correctly interpret laboratory results. All of these principles can be applied to the premature infant in the neonatal intensive care nursery as well as the full-term infant at home.

Serum antibody response to recombinant major inner capsid protein following human infection with group B rotavirus

Recombinant major inner capsid protein (VP6) of the IDIR strain of group B rotavirus (GBR) was incorporated in a solid-phase immunoassay to access antibody response to infection in humans. Expression of VP6 in insect cells permitted design of a highly sensitive assay that avoided the contaminants present in GBR antigens obtained from fecal specimens. Among patients infected with the ADRV strain of GBR in China, increased reactivity with recombinant VP6 was observed in convalescent-phase sera in comparison with sera obtained shortly after infection (P = 0.0084). Anti-VP6 antibodies were detectable as soon as 7 days after onset of gastrointestinal symptoms, and serum reactivity persisted in specimens drawn more than 1 year after infection. Solid-phase immunoassay with recombinant VP6 was next employed in order to assess anti-GBR antibody in 513 serum specimens obtained from 423 Maryland residents (ages, 7 months to 96 years; median age, 42 years). Four individuals (< 1%) exhibited serum antibodies directed against the recombinant VP6 (ages, 54 to 95 years; mean age, 77 years). Examination of 129 additional serum specimens including some from other geographic regions of the United States failed to reveal the presence of anti-GBR antibody. Anti-GBR antibody was also not detected in any of 131 serum specimens from 60 staff and residents of a nursing home in Switzerland. While infection of humans with GBR has been uncommon in these locations outside of China, the detection of serum antibodies in older individuals in the United States either indicated an unknown, age-related risk factor or may have indicated infection in the more distant past. The availability of these reagents should allow surveys for GBR infection among additional populations that have not previously been investigated.

Engineering the assembly pathway of the baculovirus-insect cell expression system

The synthesis of complex biological structures such as antibodies using recombinant DNA technology is a major biotechnological advance. Active murine antibody (IgG) oligomers, composed of two heavy (H) and two light (L) polypeptide chains, have been expressed and secreted by the baculovirus-insect cell expression system. Unfortunately, expression of the functional antibodies is accompanied by the formation of abnormal protein complexes and aggregates in which the polypeptide chains are bound together into incorrect associations. The formation of these abnormal complexes or protein aggregates in insect cells may be caused by insufficient intracellular levels of two catalytic proteins, immunoglobulin binding protein (BiP or GRP78), and protein disulfide isomerase (PDI). Consequently, we obtained the genes coding for murine BiP and PDI and cloned the genes into the baculovirus vector (Autographa californica nuclear polyhedrosis virus) to obtain AcBB-BiP and AcBB-PDI. Infection of Spodoptera frugiperda (Sf-9) insect cells with these two baculoviruses yielded recombinant proteins of the correct size that were recognized by antibodies to these proteins. Cloning these genes into the baculovirus vector is one approach to engineering the assembly pathway in order to lower aggregation and increase production of functionally active proteins and oligomers.

Diagnostic utility of PCR-enzyme immunoassay, culture, and serology for detection of Chlamydia pneumoniae in symptomatic and asymptomatic patients

To assess the utility of PCR-enzyme immunoassay (EIA) for diagnosis of acute infection with Chlamydia pneumoniae, we compared tissue culture, PCR-EIA, direct fluorescent-antibody (DFA) stain, and serology in studies with 56 patients with respiratory symptoms and 80 asymptomatic persons. Thirty-five patients were positive by either culture or PCR-EIA, and 101 were negative by both assays. Thirty specimens from symptomatic patients and one from an asymptomatic patient were culture positive; 23 of these were also PCR-EIA positive. Of the eight culture-positive, PCR-EIA-negative specimens, five were DFA negative and three were DFA positive. Four additional specimens were culture negative and PCR-EIA positive; of these, three were DFA positive and one was DFA negative. When we used culture- and/or DFA-positive results as a reference or "gold standard," the sensitivity and specificity of PCR were 76.5 and 99.0%, respectively. When we used PCR- and/or DFA-positive results as the reference, the sensitivity of culture was 87.5%. On the basis of single acute serum specimens, only 8 of these 35 patients had diagnostic antibody titers. Of the asymptomatic patients, 75% had immunoglobulin G or immunoglobulin M antibody to C. pneumoniae; 15 (18.8%) of these had antibody levels considered to be diagnostic of acute infection. This multicenter study indicates that culture and/or PCR-EIA is more reliable for prompt diagnosis of C. pneumoniae infection than single-point serology alone.

Detection of rat, porcine, and bovine group B rotavirus in fecal specimens by solid-phase enzyme immunoassay

An enzyme immunoassay that uses easily regenerated reagents was developed and evaluated for the ability to detect group B rotaviruses (GBR) in fecal specimens. Homologous rat GBR and heterologous porcine and bovine GBR were detected by this immunoassay, although a human GBR isolate was not. This immunoassay should prove useful in studies of GBR infections of animals.

Group B rotavirus VP2: sequence analysis, expression, and gene coding assignment

The second largest genomic segment of the IDIR strain (infectious diarrhea of infant rats) of group B rotavirus (GBR) was completely sequenced, cloned, and expressed in insect cells, and its gene coding assignment was determined. The sequence of IDIR virus gene 2 (IDIRg2) contained 2847 bp with a single, long open reading frame that encoded a deduced polypeptide of 934 amino acids (M(r) 106 kDa, pI 5.325). BestFit homology indicated that the predicted amino acid sequence of IDIRg2 shared 46.5% similar and 19.8% identical sequences with VP2 of the SA11 strain of group A rotavirus. The polypeptide product encoded by this gene was synthesized in insect cells by means of a baculovirus expression vector and employed to elucidate the corresponding gene to protein coding assignment. Recombinant IDIRg2 product maintained virion antigenic epitopes as evidenced by reactivity with convalescent antisera from infant rat pups infected with the IDIR agent. Reactivity with antisera from heterologous human and porcine GBR strains was also observed. Antibody directed against recombinant IDIRg2 product specifically reacted with VP2 of IDIR virus and a human strain of GBR (ADRV) obtained from fecal specimens. These experiments identified the IDIRg2 product as the VP2 core protein of the IDIR virus strain of GBR.

Expression and sequence analysis of gene 7 of the IDIR agent (group B rotavirus): similarity with NS53 of group A rotavirus

The seventh genomic segment of the IDIR strain of group B rotavirus was cloned, sequenced, and expressed in vitro in order to evaluate the gene coding assignment by comparison with group A rotaviruses (GAR). Viral genomic RNA for these reactions was obtained directly from fecal specimens of infected infant rats. IDIR virus gene 7 (IDIRg7) contained 1276 bp. Both 5' and 3' termini resembled those reported for other IDIR virus genomic segments. Two open reading frames (ORF) were predicted from the gene sequence: a long ORF from bases 258-1217 and a short ORF from bases 41-385. The first AUG of the long ORF was flanked by sequences associated with highly efficient translation, but less efficient translation was predicted for the short ORF. In vitro transcription and translation of IDIRg7 demonstrated a product consistent with polypeptide synthesis from the long ORF but not the short ORF. Convalescent rat antibody directed against the IDIR agent specifically immunoprecipitated the IDIRg7 protein and indicated that the in vitro translation product was indeed encoded by the virus genome. Thus, the untranslated 5' region of IDIRg7 was longer than that previously described for any major rotavirus product. Comparison of the IDIRg7 sequence indicated 51% similarity and 18% identity with the amino acid residues of NS53 of the SA11 strain of GAR. However, the sequence of IDIRg7 did not share the putative zinc binding region postulated for NS53 of rotavirus groups A and C. It will be of interest in future experiments to evaluate the function of the IDIRg7 product following large-scale synthesis by alternative expression systems such as vaccinia or baculovirus.

Detection of Chlamydia pneumoniae by polymerase chain reaction-enzyme immunoassay in an immunocompromised population

Chlamydia pneumoniae has now been associated with pneumonia, bronchitis, pharyngitis, acute chest syndrome of sickle cell disease, and asthma. Because of the difficulty of primary isolation and tissue-culture adaptation of this organism, we used a previously developed polymerase chain reaction-enzyme immunoassay (PCR-EIA) to screen 132 culture-negative bronchoalveolar lavage (BAL) specimens from 108 immunocompromised patients (34% of whom were positive for human immunodeficiency virus) and 7 healthy volunteers. Thirteen specimens (9.8%) from 12 immunocompromised patients (11.1%) gave a positive result; one patient had two positive specimens obtained 3 days apart. No healthy volunteer had a PCR-EIA-positive BAL specimen. Twelve (11.1%) of the immunocompromised patients also had diagnostic levels of antibody. Four patients had positive results in both PCR-EIA and serological tests. Thus 20 (18.5%) of the 108 patients had laboratory evidence of C. pneumoniae infection. These data indicate that diagnosis of acute infection with C. pneumoniae can be established more rapidly and reliably by PCR-EIA than by culture or serology, particularly among immunocompromised patients, in whom serological changes in response to infection are relatively undependable. With an infection rate of 11.1% according to PCR-EIA, C. pneumoniae should be considered in the evaluation and treatment of pneumonia in immunocompromised patients.

Gene 5 of the IDIR agent (group B rotavirus) encodes a protein equivalent to NS34 of group A rotavirus

Gene 5 of the IDIR strain of group B rotavirus was cloned, sequenced, and expressed in RBC lysates in order to identify the coding assignment. The complete nucleic acid sequence of IDIR gene 5 included 1306 bases and encoded a single long open reading frame of 390 amino acids with a predicted molecular weight of 44.8 kDa. Comparison of the predicted amino acid sequence indicated substantial identity with the NS34 protein of group A rotaviruses (GAR). Like GAR NS34, the product deduced from IDIR agent gene 5 was predicted to exhibit a high degree of alpha helix secondary structure and a relatively low pl (4.6). In vitro translation of gene 5 resulted in synthesis of a protein which was specifically immunoprecipitated by convalescent antibody obtained from infant rats following infection with the IDIR agent, confirming that this product was of viral origin. Under non-reducing conditions, products as large as 200 kDa were also noted in SDS-PAGE. Formation of oligomers by GAR NS34 has previously been observed, indicating that this feature is probably a general characteristic among rotavirus NS34 and may relate to the functional role of the protein in viral replication.

Phylogenetic relationship of Chlamydia pneumoniae to Chlamydia psittaci and Chlamydia trachomatis as determined by analysis of 16S ribosomal DNA sequences

The 16S ribosomal DNA sequence of Chlamydia pneumoniae was determined and compared with the corresponding gene sequences of Chlamydia psittaci and Chlamydia trachomatis. C. pneumoniae has been reported to exhibit little chromosomal DNA homology with the other chlamydial species, and its phylogenetic relationships within the genus Chlamydia have not been described. A polymerase chain reaction was employed to determine the 16S rRNA gene sequence of C. pneumoniae. Ten primers from the C. psittaci sequences were used to amplify a C. pneumoniae template in overlapping segments of the gene. Sequence data for 1,554 bases indicated that the levels of homology of C. pneumoniae with C. psittaci and C. trachomatis were 96.19 and 94.07%, respectively. These data support the results of previous biochemical and developmental studies indicating that C. pneumoniae is more closely related to C. psittaci than to C. trachomatis.

Identification and expression of the outer capsid protein (VP4) of the IDIR strain of group B rotavirus

The polypeptide encoded by gene 3 of the IDIR strain of group B rotavirus (GBR) was synthesized by means of a baculovirus expression system. Immunoblot analysis identified the IDIR virus gene 3 product as analogous to the outer capsid protein, VP4, encoded by gene 4 of group A rotaviruses (GAR). This coding assignment had previously been difficult to establish by sequence comparisons, since IDIR virus gene 3 shared < 20% identical amino acid sequences with any GAR protein. Trypsin digestion of the gene 3 protein resulted in the appearance of a product indistinguishable in size from the VP5* outer capsid protein of IDIR agent virions. The recombinant IDIR virus VP4 maintained at least some antigenic epitopes of the native virion protein, as evidenced by reactivity with convalescent antibody obtained following infection of infant rat pups with the IDIR agent. Reactivity was also demonstrated with antisera directed against bovine and porcine isolates of GBR as well as with ADRV, a human strain of GBR.

Baculovirus expression of gene 6 of the IDIR strain of group B rotavirus (GBR): coding assignment of the major inner capsid protein

The polypeptide product of gene 6 of the IDIR strain of group B rotavirus was synthesized by means of a baculovirus expression system in order to confirm the coding assignment of the gene and to develop reagents broadly reactive with heterologous strains of Group B rotaviruses (GBR). Earlier experiments indicated that IDIR virus gene 6 encoded the group-specific, major inner capsid protein, but direct confirmation of this coding assignment was not previously reported. The expression of IDIR virus gene 6 from baculovirus recombinants resulted in production of a protein with an apparent molecular weight equivalent to that deduced from the gene sequence (44 kDa). In addition, larger recombinant proteins were also observed, and these appeared to be consistent in size with oligomers of the primary VP6 product. The expressed protein reacted with antibody directed against the IDIR agent and other strains of GBR, but no reaction was observed with antibody directed against group A rotavirus. Serologic reactivity was also observed between the gene 6 product and a monoclonal antibody directed against the GBR group-specific antigen. Antibody directed against the recombinant gene 6 product specifically reacted with the IDIR virus major inner capsid protein in an immunoblot format. These experiments conclusively demonstrated that IDIR virus gene 6 encoded the major inner capsid protein and confirmed the presence of group B-specific antigenic epitopes on the protein.

Sequence analysis of group B rotavirus gene 1 and definition of a rotavirus-specific sequence motif within the RNA polymerase gene

The complete nucleic acid sequence was determined for the largest genomic segment of the IDIR strain of group B rotavirus and compared with RNA polymerase genes of rotavirus groups A and C as well as other RNA viruses. IDIR gene 1 contained 3509 bases with a single, long open reading frame which encoded a deduced polypeptide of 1159 amino acids (MW = 131.6 kDa; pl 8.851). The deduced amino acid sequence of IDIR gene 1 shared 50% similar sequences and 27.6% identical sequences with VP1 of the RF strain of group A rotavirus. IDIR gene 1 also contained 45.4% similar and 26.5% identical amino acid sequences in comparison with gene 1 of the Cowden strain of group C rotavirus. Amino acids 643-689 of IDIR gene 1 corresponded to the conserved viral RNA polymerase domains, "SG . . . T . . . NS . . N" and "GDD." Within these domains, group A, B, and C rotaviruses displayed substantial homologies that were not shared with other RNA viruses. These sequences indicated the presence of highly conserved structural or functional components among groups of rotaviruses which were otherwise quite heterogeneous. The identification of rotavirus-specific residues within RNA polymerase sequence may prove valuable in devising strategies aimed at the control of rotavirus replication and infection.

Similarity of Chlamydia pneumoniae strains in the variable domain IV region of the major outer membrane protein gene

DNA was amplified by polymerase chain reaction from the gene encoding the major outer membrane protein (MOMP) of Chlamydia pneumoniae in order to examine the relatedness of strains isolated from diverse geographical regions. Primers for this reaction were chosen to span a 207-bp region comparable to that of the fourth variable segment of the MOMP gene of Chlamydia trachomatis. Among C. trachomatis, sequence heterogeneity is characteristic within variable sequence domain IV (VDIV) and correlates with serovar type. In contrast, sequence analysis of polymerase chain reaction products from 13 C. pneumoniae isolates indicated that all tested strains were identical in this segment of the MOMP gene. The predicted amino acid sequences from the C. pneumoniae VDIV gene products shared only 13.3 to 30% homology with published VDIV regions from serovars of C. trachomatis. Homology of these VDIV amino acid sequences with sequences from strains of C. psittaci ranged from 45.7 to 60%. The sequence conservation of the VDIV region of the MOMP gene indicates that C. pneumoniae strains may be more genetically homogeneous than C. trachomatis or Chlamydia psittaci strains. Future investigations of antigenic diversity among C. pneumoniae strains should be aimed at the evaluation of variation in other regions of the C. pneumoniae genome.

Terminal sequence conservation among the genomic segments of a group B rotavirus (IDIR strain)

Terminal nucleic acid sequences were determined for all 11 segments of the IDIR strain of group B rotavirus. Consensus sequences were defined at both ends of the (+) RNA strands as 5' GGN(A/U)NA(A/U)(A/U)(A/U)---and---(A/U)NA(A/G)N(A/C)(C/A)CC3 '. The 5' and 3' terminal sequences of the (+) strand IDIR RNA were not complementary to one another. The IDIR terminal sequences and those of group A rotaviruses (GAR) were similar in that each of the (+) strands began with "GG" and ended with "CC." Otherwise, the IDIR terminal sequences did not match the consensus sequences that have been reported for the ends of the GAR genomic segments.

Molecular cloning, sequence analysis, in vitro expression, and immunoprecipitation of the major inner capsid protein of the IDIR strain of group B rotavirus (GBR)

The sixth genomic segment of the infectious diarrhea of infant rats (IDIR) strain of group B rotavirus (GBR) was cloned from double-stranded RNA purified from infected rat feces. Sequence comparison with group A rotaviruses (GAR) and the human ADRV strain of GBR indicated that IDIR gene 6 encoded the major inner capsid protein. The nucleic acid sequences of the two GBR genes were 72.9% conserved, and 83.4% of the amino acids were identical. Sequence substitutions between IDIR and ADRV were more numerous than reported for heterologous GAR strains, indicating that the two GBR strains may have diverged from one another over a longer period of time. Despite the sequence heterogeneity exhibited by the major inner capsid proteins of ADRV and IDIR, hydrophilicity plots of the two gene products were nearly indistinguishable. The GBR hydrophilicity plots displayed little similarity with those of rotavirus groups A or C, indicating substantial differences in the structures of those major inner capsid proteins. In vitro transcription and translation of IDIR gene 6 yielded a polypeptide product consistent in size with that predicted from the deduced amino acid sequence and the virion major inner capsid protein. The IDIR 6 polypeptide was immunoprecipitated by antisera directed against IDIR as well as antisera directed against ADRV and a heterologous bovine strain of GBR. No immunoprecipitation was observed with control sera or antisera directed against GAR. These results confirmed that group-specific epitopes were displayed by the major inner capsid protein encoded by IDIR gene 6. Reactivity with heterologous GBR antisera also indicated that the IDIR gene 6 product may prove useful as a standard reagent in immunoassays for the detection of GBR.

Identification of Chlamydia pneumoniae by DNA amplification of the 16S rRNA gene

Chlamydia pneumoniae is an important cause of respiratory disease in humans, but diagnosis of C. pneumoniae is hindered by difficulties in the in vitro growth of the organism. In order to improve detection and identification, we recently developed a polymerase chain reaction (PCR) assay which uses oligonucleotide primers specific for C. pneumoniae. The nucleic acid sequence was determined for the 16S rRNA of C. pneumoniae, and regions in which C. pneumoniae differed from both Chlamydia psittaci and Chlamydia trachomatis were identified. Oligonucleotide primers corresponding to these unique regions were then synthesized and used in a PCR for the detection of C. pneumoniae. The C. pneumoniae-specific primers permitted the identification of six isolates of C. pneumoniae, but no reaction was observed with the 15 serovars of C. trachomatis or two strains of C. psittaci. PCR should prove to be valuable in confirming the identification of C. pneumoniae and in the diagnosis of C. pneumoniae infections.

Identification of cognate genes among heterologous strains of group B rotavirus

The genetic relatedness of group B rotavirus (GBR) strains has previously been documented by hybridization with probes derived from whole genomic sequences, but the relationship of individual genes of heterologous GBR strains has not been evaluated. Definition of cognate GBR genes would facilitate investigation of the determinants of group specificity, serotype identity, and neutralization epitopes. Therefore, we investigated the genetic relatedness of three GBR strains by means of Northern (RNA) blot hybridization with isotopically labeled probes prepared from each of the 11 genes of the IDIR strain of GBR. Under low-stringency conditions, hybridization between each of the IDIR gene probes and genomic RNA from the ADRV strain of GBR was observed. Genomic RNA obtained from a bovine strain of GBR hybridized with 9 of the 11 IDIR gene probes. In most cases, cognate genes of each of the GBR strains appeared to migrate to similar positions following polyacrylamide gel electrophoresis. However, the electropherotype positions of GBR genes 5, 6, and 7 were different for each of the three GBR strains. Identification of these genomic segments among GBR strains should prove helpful in future evaluations of GBR structure and function.