Rise In Antibody Titer Research Articles

Prevalence and Antibiogram Pattern of Salmonella enterica Serotypes inGarhwal Region: First Report from Foothills of Himalayas

Introduction: Enteric fever, caused by Salmonella enterica subsp. Enterica serotype Typhi and Paratyphi, is endemic in India with an incidence of 102–2219/100,000 populations. The definitive diagnosis of enteric fever in patients with compatible clinical picture is isolation of Salmonellae from blood, bone marrow, stool or urine, and demonstration of four‑fold rise in antibody titer to both O and H antigen of the organism between acute and convalescent‑phase sera. Aim: The aim of the study was to study the prevalence of various serotypes of S. enterica and their antibiogram in foot hills of Himalayas. Materials and Methods: During February 2012–January 2013, all clinically suspected patients were screened for enteric fever by Widal tube agglutination test. For the isolation of etiology, venous blood, stool and urine specimen were obtained from patients with antibody titer of ≥80 and 160 for anti‑O agglutinin and anti‑H agglutinin of Salmonella typhi, respectively, and ≥20 for anti-H agglutinin of S. paratyphi A and S. paratyphi B. Characterization and antibiogram determination of the isolates was done by conventional microbiological methods including Kirby–Bauer’s disc diffusion technique. Result: Among 1173 suspected cases, 373 showed a high titer of antibodies against O (≥80), H (≥160), AH (≥20), and BH (≥20) antigens. A total of 81 isolates were obtained from 76 patients (29 from blood and 49 from stool and three from urine), of which 54 were identified as Salmonella typhi, 20 as Paratyphi A and seven as Paratyphi B. Extended‑spectrum beta‑lactamase production was observed in four isolates of S. typhi. Ciprofloxacin followed by co‑trimoxazole was resistant to 46.5 and 36.5% of the isolates, respectively. Conclusion: This report indicates a significant percentage of drug resistance in S. enterica serotypes in Garhwal region. Periodic monitoring of the antibiogram pattern along with the implementation of strict antibiotic policies and patient education is needed. Keywords: Blood culture, extended‑spectrum beta‑lactamase, Salmonella typhi, typhoid fever, Widal test.

Naturally acquired IgG antibodies to thrombospondin-related anonymous protein of Plasmodium vivax (PvTRAP) in Thailand predominantly elicit immunological cross-reactivity.

Thrombospondin-related anonymous protein (TRAP) is a prime candidate for a malaria vaccine. Antibodies to Plasmodium vivax TRAP (PvTRAP) occur upon natural infection while specific antigenic domains remain to be addressed. The PvTRAP sequences were determined from 73 P.vivax isolates from Tak and Ubon Ratchathani provinces collected in 2013. The recombinant proteins representing four variants each for domain II (A domain) and domain IV (thrombospondin repeat region) of PvTRAP circulating in these areas were used as antigens in enzyme-linked immunosorbent assay against 246 serum samples from P.vivax-infected patients in both provinces collected during 2013 and 2014. The prevalence of total IgG antibodies to at least one variant antigen of domain II and domain IV was 63.8% and 71.5%, respectively. Differential IgG antibody responses to these variant antigens of each domain were observed. Total IgG antibody responses to the variant antigens of each domain upon pairwise comparisons were highly correlated, suggesting immunological cross-reactivity in the majority of serum samples. A smaller proportion of serum samples contained non-cross-reactive antibodies to variants of each domain; particularly domain II in which amino acid differences significantly influenced antibody recognition. Previous malaria exposure positively affected antibody responses to domain IV. Positive seroconversion and rising antibody titres occurred within a few weeks after resolution of infections. Both domains II and IV are targets of naturally acquired IgG antibodies. Despite sequence variation in these domains, most antibody responses were cross-reactive. A cross-sectional evaluation of antibodies to PvTRAP during acute infection could underestimate the seroprevalence.

Design and immune characterization of a novel Neisseria gonorrhoeae DNA vaccine using bacterial ghosts as vector and adjuvant

Gonorrhea, an important sexually transmitted disease, is becoming a growing public health problem around the globe. Vaccination is considered the best long-term approach for control of infection. In this study, we designed a novel Neisseria gonorrhoeae (N. gonorrhoeae) DNA vaccine delivered by bacterial ghosts and characterized its immune responses in vitro and in vivo. Our results demonstrate that bacterial ghosts greatly promoted BMDCs maturation and activation. Bacterial ghosts loaded with N. gonorrhoeae DNA vaccine were efficiently taken up by mouse macrophage RAW264.7 cells. Furthermore, oral immunization with the ghost vaccine candidate elicited greater CD4+ and CD8+ T cell responses and induced higher IgG responses than N. gonorrhoeae DNA vaccine alone. In addition, mice immunized with the vaccine candidate responded with a significant rise in bactericidal antibody titer. These results suggest that bacterial ghosts may function as a vaccine adjuvant by promoting BMDCs maturation, which in turn enhances the immune responses to the vaccine antigens. This study also highlights the potential of using bacterial ghosts as antigen delivery system in the development of an efficacious gonorrhea vaccine.

Risk factors for human acute leptospirosis in northern Tanzania.

IntroductionLeptospirosis is a major cause of febrile illness in Africa but little is known about risk factors for human infection. We conducted a cross-sectional study to investigate risk factors for acute leptospirosis and Leptospira seropositivity among patients with fever attending referral hospitals in northern Tanzania.MethodsWe enrolled patients with fever from two referral hospitals in Moshi, Tanzania, 2012–2014, and performed Leptospira microscopic agglutination testing on acute and convalescent serum. Cases of acute leptospirosis were participants with a four-fold rise in antibody titers, or a single reciprocal titer ≥800. Seropositive participants required a single titer ≥100, and controls had titers <100 in both acute and convalescent samples. We administered a questionnaire to assess risk behaviors over the preceding 30 days. We created cumulative scales of exposure to livestock urine, rodents, and surface water, and calculated odds ratios (OR) for individual behaviors and for cumulative exposure variables.ResultsWe identified 24 acute cases, 252 seropositive participants, and 592 controls. Rice farming (OR 14.6), cleaning cattle waste (OR 4.3), feeding cattle (OR 3.9), farm work (OR 3.3), and an increasing cattle urine exposure score (OR 1.2 per point) were associated with acute leptospirosis.ConclusionsIn our population, exposure to cattle and rice farming were risk factors for acute leptospirosis. Although further data is needed, these results suggest that cattle may be an important source of human leptospirosis. Further investigation is needed to explore the potential for control of livestock Leptospira infection to reduce human disease.

Live Respiratory Syncytial Virus (RSV) Vaccine Candidate Containing Stabilized Temperature-Sensitivity Mutations Is Highly Attenuated in RSV-Seronegative Infants and Children

Respiratory syncytial virus (RSV) is the most important viral cause of severe respiratory illness in young children and lacks a vaccine. RSV cold-passage/stabilized 2 (RSVcps2) is a modification of a previously evaluated vaccine candidate in which 2 major attenuating mutations have been stabilized against deattenuation. RSV-seronegative 6-24-month-old children received an intranasal dose of 105.3 plaque-forming units (PFU) of RSVcps2 (n = 34) or placebo (n = 16) (International Maternal Pediatric Adolescent AIDS Clinical Trials protocol P1114 and companion protocol CIR285). RSV serum neutralizing antibody titers before and 56 days after vaccination, vaccine virus infectivity (defined as vaccine virus shedding detectable in nasal wash and/or a ≥4-fold rise in serum antibodies), reactogenicity, and genetic stability were assessed. During the following RSV transmission season, participants were monitored for respiratory illness, with serum antibody titers measured before and after the season. A total of 85% of vaccinees were infected with RSVcps2 (median peak titer, 0.5 log10 PFU/mL by culture and 2.9 log10 copies/mL by polymerase chain reaction analysis); 77% shed vaccine virus, and 59% developed a ≥4-fold rise in RSV-serum neutralizing antibody titers. Respiratory tract and/or febrile illness occurred at the same rate (50%) in the vaccine and placebo groups. Deattenuation was not detected at either of 2 stabilized mutation sites. RSVcps2 was well tolerated and moderately immunogenic and had increased genetic stability in 6-24-month-old RSV-seronegative children. NCT01852266 and NCT01968083.

Evidence for Rise in Meningococcal Serogroup C Bactericidal Antibody Titers in the Absence of Booster Vaccination in Previously Vaccinated Children.

The introduction of meningococcal serogroup C (MenC) conjugate vaccines in the United Kingdom and Australia led to an impressive decline in the incidence of invasive disease. This study examined bactericidal antibody titers over time in the UK and Australian children who received a MenC conjugate vaccine in early childhood to test the hypothesis that ongoing boosting of immunity in the absence of further doses of vaccine in some children may contribute to ongoing protection from disease. Serum bactericidal assay using rabbit complement (rSBA) titers at each follow-up visit were compared with all preceding visits to identify any ≥4-fold rise in titers. The proportion of children with a ≥4-fold rise in rSBA titers in paired sera at any visit-to-visit comparison was calculated. Of 392 children with at least one set of paired sera in the Australian cohort, 72 (18.4%) had a ≥4-fold increase in rSBA titers at least one year after vaccination, including six children (1.5%) who showed evidence of boosting twice. Of 234 children with at least one set of paired sera in the UK cohort, 39 (16.7%) had a ≥4-fold rise in rSBA titers at least one year after vaccination including 2 children (0.9%) with evidence of boosting twice. A substantial minority of children immunized with MenC conjugate vaccine in early childhood had a rise in bactericidal antibody titers in the years after immunization in the absence of booster vaccination. This occurs most commonly at around 6-7 years of age corresponding to school entry and greater social mixing and might indicate exposure to MenC carriage.

Variables affecting laboratory diagnosis of acute rickettsial infection

The reference standard for the confirmation of a recent rickettsial infection is by the observation of a four-fold or greater rise in antibody titres when testing paired acute and convalescent (two to four weeks after illness resolution) sera by serological assays (Figure 1). At the acute stage of illness, diagnosis is performed by molecular detection methods most effectively on DNA extracted from tissue biopsies (eschars, skin rash, and organs) or eschar swabs. Less invasive and more convenient samples such as blood and serum may also be used for detection; however, the low number of circulating bacteria raises the possibility of false negative results. Optimal sampling practices and enhanced sensitivity must therefore be considered in order to provide a more accurate laboratory diagnosis.

Prevalence and antibiogram pattern of Salmonella enterica serotypes in Garhwal Region: First report from foothills of himalayas

Introduction: Enteric fever, caused by Salmonella enterica subsp. Enterica serotype Typhi and Paratyphi, is endemic in India with an incidence of 102–2219/100,000 populations. The definitive diagnosis of enteric fever in patients with compatible clinical picture is isolation of Salmonellae from blood, bone marrow, stool or urine, and demonstration of four‑fold rise in antibody titer to both O and H antigen of the organism between acute and convalescent‑phase sera. Aim: The aim of the study was to study the prevalence of various serotypes of S. enterica and their antibiogram in foot hills of Himalayas. Materials and Methods: During February 2012–January 2013, all clinically suspected patients were screened for enteric fever by Widal tube agglutination test. For the isolation of etiology, venous blood, stool and urine specimen were obtained from patients with antibody titer of ≥80 and 160 for anti‑O agglutinin and anti‑H agglutinin of Salmonella typhi, respectively, and ≥20 for anti-H agglutinin of S. paratyphi A and S. paratyphi B. Characterization and antibiogram determination of the isolates was done by conventional microbiological methods including Kirby–Bauer’s disc diffusion technique. Result: Among 1173 suspected cases, 373 showed a high titer of antibodies against O (≥80), H (≥160), AH (≥20), and BH (≥20) antigens. A total of 81 isolates were obtained from 76 patients (29 from blood and 49 from stool and three from urine), of which 54 were identified as Salmonella typhi, 20 as Paratyphi A and seven as Paratyphi B. Extended‑spectrum beta‑lactamase production was observed in four isolates of S. typhi. Ciprofloxacin followed by co‑trimoxazole was resistant to 46.5 and 36.5% of the isolates, respectively. Conclusion: This report indicates a significant percentage of drug resistance in S. enterica serotypes in Garhwal region. Periodic monitoring of the antibiogram pattern along with the implementation of strict antibiotic policies and patient education is needed. Keywords: Blood culture, extended‑spectrum beta‑lactamase, Salmonella typhi, typhoid fever, Widal test.

Pneumococcal responses are similar in Papua New Guinean children aged 3-5 years vaccinated in infancy with pneumococcal polysaccharide vaccine with or without prior pneumococcal conjugate vaccine, or without pneumococcal vaccination

Trial designIn an earlier trial, Papua New Guinean (PNG) children at high risk of pneumococcal disease were randomized to receive 0 or 3 doses of 7-valent pneumococcal conjugate vaccine (PCV7), followed by a single dose of 23-valent pneumococcal polysaccharide vaccine (PPV23) at 9 months of age. We here studied in a non-randomized follow-up trial the persistence of pneumococcal immunity in these children at 3–5 years of age (n = 132), and in 121 community controls of a similar age with no prior pneumococcal vaccination.MethodsCirculating IgG antibody titers to all PCV7 and PPV23-only serotypes 2, 5 and 7F were measured before and after challenge with 1/5th of a normal PPV23 dose. Serotype-specific memory B-cells were enumerated at 10 months and 3–5 years of age for a subgroup of study children.ResultsSerotype-specific IgG antibody titers before and after challenge were similar for children who received PCV7/PPV23, PPV23 only, or no pneumococcal vaccines. Before challenge, at least 89% and 59% of children in all groups had serotype-specific titers ≥ 0.35μg/ml and ≥ 1.0 μg/ml, respectively. Post-challenge antibody titers were higher or similar to pre-challenge titers for most children independent of pneumococcal vaccination history. The rise in antibody titers was significantly lower when pre-challenge titers were higher. Overall the relative number of serotype-specific memory B-cells remained the same or increased between 10 months and 3–5 years of age, and there were no differences in serotype-specific memory B-cell numbers at 3–5 years of age between the three groups.ConclusionsImmunity induced by PCV7 and/or PPV23 immunization in infancy does not exceed that of naturally acquired immunity in 3-5-year-old children living in a highly endemic area. Also, there was no evidence that PPV23 immunization in the first year of life following PCV7 priming induces longer-term hypo-responsiveness.Trial registrationClinicaltrials.gov NCT01414504 and NCT00219401.

Immunogenicity and protective efficacy of inactivated equine influenza (H3N8) virus vaccine in murine model

Equine influenza viruses (EIVs) are responsible for acute contagious respiratory infection in equines and the disease remains a major threat for equine population throughout the world despite vaccination strategies in place. The present study was aimed to assess the suitability of BALB/c mice as a potential small animal model for preliminary screening of EI vaccine candidates. For this, we evaluated the immunogenicity and protective efficacy of an inactivated EIV (H3N8) vaccine in BALB/c mouse model after challenge with homologous H3N8 virus (Clade 2 virus, Florida sublineage) through serology, clinical signs, gross and histopathology lesions with grading, immunohistochemistry and virus quantification. Serological responses in immunized mice were evaluated by haemagglutination inhibition assay (HAI) and antibodies were subtyped by ELISA. The vaccine induced optimum protective antibody titre on 49 dpi along with balanced Th1/Th2 responses. Immunized mice were well protected against EIV challenge as evident by significant rise in serum antibody titre which concurred with mild clinical signs, early recovery, lower gross and histopathological lesions score, less severe intensity of viral antigen distribution, restricted virus replication in respiratory tract and less virus detection in nasal washes for short duration. The duration of the viral load was also lower and only for brief period as compared to unvaccinated challenged mice. In conclusion, induction of H3N8 specific antibody response and protection against H3N8 challenge proves that egg grown inactivated H3N8 whole virus vaccine would provide an effective intercession against H3N8 virus. In addition, BALB/c mouse can serve as an attractive tool for adjudging protective efficacy of vaccine candidates prior to final testing in equines.

Evaluation of a multicomponent vaccine in dogs

The concept of combined viral and bacterial vaccines has been tried in cattle, canine and humans. Use of multicomponent vaccines has numerous advantages over individual vaccine. In this study, apparently healthy 8-9 weeks old 41 puppies were divided into 2 groups. 31 puppies (test group) were vaccinated subcutaneously with a commercially available multicomponent vaccine containing live attenuated strains of Canine Distemper virus, Canine Adenovirus type 2, Canine Parvo virus and Canine Parainfluenza virus and inactivated antigens of Leptospira canicola and Leptospira icterohemorrhagiae. 10 puppies were kept unvaccinated (control). Test group puppies were given a booster after 4 weeks of primary vaccination. Serum samples from both the groups were collected on 4 occasions (0th, 28th, 42nd and 90th day) and were tested for antibody titres against Canine Distemper virus and Canine Adenovirus type 2 by Serum Neutralization test, against Canine Parvovirus and Canine Parainfluenzavirus by Haemagglutination Inhibition test and against Leptospira canicola and L. icterohemorrhagiae by Microscopic Agglutination Test. A significant rise (P 0.5) in antibody titres was observed against all the antigens after vaccination. The control group did not show significant variation in the antibody titres. All puppies vaccinated subcutaneously with this vaccine did not evoke any local/ adverse reactions.

The Household Influenza Vaccine Effectiveness Study: Lack of Antibody Response and Protection Following Receipt of 2014-2015 Influenza Vaccine.

Antigenically drifted A(H3N2) viruses circulated extensively during the 2014-2015 influenza season. Vaccine effectiveness (VE) was low and not significant among outpatients but in a hospitalized population was 43%. At least one study paradoxically observed increased A(H3N2) infection among those vaccinated 3 consecutive years. We followed a cohort of 1341 individuals from 340 households. VE against laboratory-confirmed influenza was estimated. Hemagglutination-inhibition and neuraminidase-inhibition antibody titers were determined in subjects ≥13 years. Influenza A(H3N2) was identified in 166 (12%) individuals and B(Yamagata) in 34 (2%). VE against A(H3N2) was -3% (95% confidence interval [CI]: -55%, 32%) and similarly ineffective between age groups; increased risk of infection was not observed among those vaccinated in 2 or 3 previous years. VE against influenza B(Yamagata) was 57% (95% CI: -3%, 82%) but only significantly protective in children <9 years (87% [95% CI: 43%, 97%]). Less than 20% of older children and adults had ≥4-fold antibody titer rise against influenza A(H3N2) and B antigens following vaccination; responses were surprisingly similar for antigens included in the vaccine and those similar to circulating viruses. Antibody against A/Hong Kong/4801/14, similar to circulating 2014-2015 A(H3N2) viruses and included in the 2016-2017 vaccine, did not significantly predict protection. Absence of VE against A(H3N2) was consistent with circulation of antigenically drifted viruses; however, generally limited antibody response following vaccination is concerning even in the context of antigenic mismatch. Although 2014-2015 vaccines were not effective in preventing A(H3N2) infection, no increased susceptibility was detected among the repeatedly vaccinated.

Safety and immunogenicity of a live attenuated influenza H5 candidate vaccine strain A/17/turkey/Turkey/05/133 H5N2 and its priming effects for potential pre-pandemic use: a randomised, double-blind, placebo-controlled trial

SummaryBackgroundThe emergence of highly pathogenic avian influenza H5N1 viruses has raised concerns about their pandemic potential. Vaccination is the most effective way of preventing influenza. In this study, we investigated the safety and immunogenicity of an avian H5N2 live attenuated influenza vaccine (LAIV H5N2) in healthy Thai adults and its priming immune responses with an H5N1 inactivated vaccine boost.MethodsThis study was done at the Vaccine Trial Centre at Mahidol University, Bangkok, Thailand and was divided into two parts. Part 1 consisted of a randomised, double-blind, placebo-controlled trial done over 18 months. We randomly assigned (2:1) healthy Thai adults aged 18–49 years with a computer generated randomisation sequence (blocks of six) to receive either two intranasal doses (0·25 mL per nostril) of LAIV H5N2 (101 participants) or placebo (51 participants) 21 days apart. For part 2, an open-label trial was done in which previously vaccinated participants (40 from LAIV H5N2 group and 20 placebo) were given one intramuscular dose (0·5 mL) of H5N1 booster vaccine. Participants, investigators, and site-study workers were blinded from randomisation. Immune responses after subsequent immunisation were evaluated using haemagglutination-inhibition and microneutralisation assays and circulating follicular T-helper cells and plasmablast cells were measured in serum and whole blood. The trials are registered with ClinicalTrials.gov, numbers NCT01841918 and NCT02229357.FindingsBetween Feb 4, 2013, and Feb 28, 2013, 256 individuals were screened, of whom 152 participants were enrolled in part 1 of this study. LAIV H5N2 vaccine was well tolerated. Viral shedding was detected in only six (6%) of 101 participants in the vaccine group 1 day after the first vaccination and in and two (2%) of 98 participants in the group after the second vaccination. There was no serious adverse event in both groups. 51 (50%) of 101 participants in the vaccine group and 28 (55%) of 51 in the placebo group reported at least one adverse event. 80 (84%) of 95 events in the vaccine group and 32 (78%) of 43 events in the placebo groups were reportedly suspected adverse events, probably related to the vaccine; however, most were mild in nature. After two doses of vaccine, 13 (13%) of 100 participants in the vaccine group had an increase in haemagglutination-inhibition titre of more than four-fold and four (4%) of 100 vaccinees developed a rise in neutralisng antibody titre of more than four-fold. 1 year later, after a booster with an inactivated H5N1 vaccine (part 2), 39 (98%) of 40 participants who had previously been vaccinated with LAIV H5N2 had an increase in haemagglutination-inhibition titre of greater than four-fold as early as day 7 compared with three (15%) of 20 participants in the placebo group. Peak geometric mean titre (GMT) for haemagglutination-inhibition antibodies in the previously LAIV H5N2 vaccinated group (566·89 [95% CI 436·97–735·44]) were significantly higher than among those who previously received placebo (25·49 [11·82–54·96]; p<0·0001). The peak GMT by neutralising antibody assay in the H5N2 vaccinated group (1395·85 [1040·79–1872·03]) was also significantly higher than that observed in the placebo group (17·41 [9·05–33·48]; p<0·0001). Importantly, higher cross-reactive haemagglutination-inhibition antibody titres against H5N1 (clades 1, 2.1.3.2, and 2.3.4) were detected in the LAIV H5N2 experienced group than the naive group (p<0·0001).InterpretationOur data suggest that LAIV vaccination induces long-lasting memory immune responses. The limitation of this study was that part 2 was designed as a proof-of-concept study by contrast with part 1.FundingWHO.

Boosting Immune Responses Following Fractional-Dose Inactivated Poliovirus Vaccine: A Randomized, Controlled Trial.

Fractional-dose administration of inactivated poliovirus vaccine (fIPV) could increase IPV affordability and stretch limited supplies. We assessed immune responses following fIPV administered intradermally, compared with full-dose IPV administered intramuscularly, among adults with a history of oral poliovirus vaccine (OPV) receipt. We conducted a randomized, controlled noninferiority trial in Cuba. fIPV or IPV were administered on days 0 and 28; serum was collected on days 0, 7, 28, and 56 for analysis by a neutralization assay. The primary end point was seroconversion or a ≥4-fold rise in antibody titer. The noninferiority limit was 10%. The secondary end point was safety, assessed by the number and intensity of adverse reactions. A total of 503 of 534 enrolled participants (94.2%) completed all study requirements. Twenty-eight days after the first dose, 94.8%, 98.0%, and 98.0% of fIPV recipients had an immune response to poliovirus types 1, 2, and 3, respectively, compared with 98.1% (P = .06), 98.0% (P = 1.00), and 99.2% (P = .45) in the IPV arm. Noninferiority was achieved on days 7, 28, and 56 for all serotypes. No serious adverse events were reported. fIPV induced similar boosting immune responses, compared with full-dose IPV. This suggests that fIPV would be an effective strategy to boost population immunity in an outbreak situation. ACTRN12615000305527.

ABO incompatible renal transplant: Transfusion medicine perspective.

INTRODUCTION:Our study presents an analysis of the trends of ABO antibody titers and the TPE (Therapeutic Plasma Exchange) procedures required pre and post ABO incompatible renal transplant.MATERIALS AND METHODS:Twenty nine patients underwent ABO incompatible renal transplant during the study period. The ABO antibody titers were done using the tube technique and titer reported was the dilution at which 1+ reaction was observed. The baseline titers of anti-A and anti-B antibodies were determined. The titer targeted was ≤8. Patients were subjected to 1 plasma volume exchange with 5% albumin and 2 units of AB group FFP (Fresh Frozen Plasma) in each sitting. TPE procedures post-transplant were decided on the basis of rising antibody titer with/ without graft dysfunction.RESULTS:The average number of TPE procedures required was 4-5 procedures/patient in the pretransplant and 2-3/patient in the post-transplant period. An average titer reduction of 1 serial dilution/procedure was noted for Anti-A and 1.1/procedure for Anti-B. Number of procedures required to reach the target titer was not significantly different for Anti-A and Anti-B (P = 0.98). Outcome of the transplant did not differ significantly by reducing titers to a level less than 8 (P = 0.32). The difference in the Anti-A and Anti-B titers at 14th day post-transplant was found to be clinically significant (P = 0.042).CONCLUSION:With an average of 4-5 TPE procedures pretransplant and 2-3 TPE procedures post transplants, ABO incompatible renal transplantations can be successfully accomplished.

Preparation of Hyperimmune Serum against Peste Des Petits Ruminants to Be Used in Emergency Cases

Hyperimmune serum against peste des petites ruminants virus was successfully prepared in horses where it was found to have specific peste des petites ruminants virus (PPRV) neutralizing antibodies titer of 1024/ml as determined by serum neutralization test (SNT). Quality control testing of such serum revealed that it was free from bacterial, fungal and mycoplasma contaminants as tested on specific media and safe when inoculated in sheep. Passive induced immunity in sheep was persisted with a protective level up to 5 weeks post inoculation as determined by SNT and ELISA. On the other side, inoculation of PPR vaccine with antisera in sheep showed similar findings with slight rise in antibody titer. Depending on the obtained results, it could be concluded that horse anti-PPR serum is of a significant importance and can help to protect and control PPR infections especially in case of outbreaks that need rapid management.

Detection of Yersinia enterocolitica serotype O:9 in the faeces of cattle with false positive reactions in serological tests for brucellosis in Ireland

Intestinal infection by Yersinia enterocolitica serotype O:9 (YeO9) in cattle has been linked to false positive serological reactivity (FPSR) in diagnostic tests for brucellosis. Although eradicated in Ireland, brucellosis monitoring still identifies seropositive animals, usually one or two (termed singletons) per herd, which are classed as FPSR. To investigate a link between FPSR and YeO9, faeces and blood were collected from singleton FPSR cattle, and from companion animals, in eight selected herds with more than one FPSR animal, for YeO9 culture and Brucella serology. YeO9 was isolated from 76/474 (16%) FPSR singletons in 309 herds, but not from any of 621 animals in 122 control non-FPSR herds. In the FPSR herds 52/187 (27.8%) animals were culture positive, and 17% of the isolates were from seronegative animals. Seropositive animals were more likely to have a rising antibody titre when culture positive.

Assessment of immune response to a lyophilized peste-des-petits-ruminants virus vaccine in three different breeds of goats.

Aim:Immune response to a lyophilized peste-des-petits-ruminants virus (PPRV) vaccine was evaluated in three different breeds of goats.Materials and Methods:Three breeds of goats consisting six number of animals in three groups, i.e., Group A (local Assam hill goat), Group B (cross-bred), and Group C (Beetal goats) were randomly selected for evaluating the immune response to a lyophilized PPRV vaccine.Results:A higher rise in the overall mean serum antibody titer was observed in Group A (40.50±3.74) than in Group B (37.58±37.58) and Group C (35.90±3.29) during the study period.Conclusion:Initially, a negative PPRV specific serum antibody titer was recorded in all the groups at 0th day of vaccination. Serum antibody titer in the vaccinated goats started rising gradually from the 14th day post vaccination. Later higher rise in the overall mean serum antibody titer in Group A (local Assam hill goat) lead to the conclusion that higher serum antibody titer in local non-descript breed might be due to their better adaptation to the environmental condition.

Pertussis vaccination during pregnancy in Belgium: Follow-up of infants until 1 month after the fourth infant pertussis vaccination at 15 months of age

Vaccination of pregnant women with a pertussis containing vaccine is a recommended strategy in some industrialized countries, to protect young infants from severe disease. One of the effects of the presence of high titers of passively acquired maternal antibodies in young infants is blunting of immune responses to infant vaccination. We present infant immune responses to a fourth pertussis containing vaccine dose at 15 months of age, as a follow-up of previously presented data.In a prospective cohort study, women were either vaccinated with an acellular pertussis vaccine (Boostrix®) during pregnancy (vaccine group) or received no vaccine (control group).All infants were vaccinated with Infanrix Hexa® according to the standard Belgian vaccination schedule (8/12/16 weeks, 15 months). We report results from blood samples collected before and 1 month after the fourth vaccine dose. Immunoglobulin G (IgG) antibodies against pertussis toxin (PT), filamentous hemagglutinin (FHA), pertactin (Prn), tetanus toxoid (TT) and diphtheria toxoid (DT) were measured using commercially available ELISA tests. Antibody levels were expressed in International Units per milliliter.Demographic characteristics were similar in the vaccine and control group. Before the fourth vaccine dose, significantly lower antibody titers were measured in the vaccine group compared to the control group for anti-Prn IgG (p=0.003) and anti-DT IgG (p=0.023), with a steep decay of antibody titers since post-primary vaccination. One month after the fourth dose, antibody titers were only significantly lower in the vaccine group for anti-PT IgG (p=0.006). For all antigens, there was a rise in antibody titer after the fourth vaccine dose.The present results indicate still a minor blunting effect 1 month after a fourth vaccine dose for anti-PT antibodies. However, a good humoral immune response on all measured antigens was elicited in both groups of children. The clinical significance of such blunting effect is yet unknown.Clinicaltrials.gov identifier: NCT01698346.

Role of Therapeutic Plasma Exchange in Reducing ABO Titers in Patients Undergoing ABO-Incompatible Renal Transplant

Abstract Background/aims Our study presents an analysis of the trends of ABO antibody titers and the TPE (therapeutic plasma exchange) procedures required pre- and post-ABO-incompatible renal transplant. Methods Twenty-nine patients underwent ABO-incompatible renal transplant during the study period. The ABO antibody titers were done using the tube technique and titer reported was the dilution at which 1+ reaction was observed. The baseline titers of anti-A and anti-B antibodies were determined. The titer targeted was ≤8. Patients were subjected to 1 plasma volume exchange with 5% albumin and 2 units of AB group FFP (fresh frozen plasma) in each sitting. TPE procedures posttransplant were decided on the basis of rising antibody titer with/without graft dysfunction. Results The average number of TPE procedures required were 4–5procedures/patient in the pretransplant and 2–3procedures/patient in the posttransplant period. An average titer reduction of 1serial dilution/procedure was noted for anti-A and 1.1serial dilution/procedure for anti-B. Number of procedures required to reach the target titer was not significantly different for anti-A and anti-B ( p =0.9). The number of TPE procedures required pretransplant does not differ significantly with the baseline titers ( p =0.062). Outcome of the transplant did not differ significantly by reducing titers to p =0.326). The difference in the anti-A and anti-B titers at 14th day posttransplant was not found to be clinically significant ( p =0.19). Conclusion With an average of 4–5 TPE procedures pretransplant and 2–3 TPE procedures posttransplants, ABO-incompatible renal transplantations can be successfully accomplished.