Rise In Antibody Titer Research Articles

Immunogenicity and protective efficacy of Vibrio cholerae outer membrane vesicles in rabbit model

We show here that oral immunization with purified outer membrane vesicles (OMVs) of Vibrio cholerae induces a prolonged high rise in the protective antibody titre. Rabbit immune sera were vibriocidal against the homologous and against several heterologous V. cholerae strains in vitro. In addition, OMV immunization conferred significant protective immunity against subsequent bacterial challenges. Thirty OMV-immunized rabbits were challenged with different V. cholerae strains; each challenged group contained five immunized and three unimmunized animals. All the immunized rabbits survived bacterial challenges and were healthy after 24 h, except the two from each group that received the SG24 and SG06 strains, respectively, which developed watery diarrhoea. In contrast, all the unimmunized animals developed cholera-like symptoms, with a death toll of eight within 24 h of challenge. This is the first report of the induction of protective immunity by V. cholerae OMVs in a rabbit model (removable intestinal tie-adult rabbit diarrhoea) that mimics the human disease. Finally, OMVs were found to be significantly less reactogenic than the live and the heat-killed bacteria. Our studies show that oral immunization with OMVs of V. cholerae may induce long-term immunity and may be useful as a 'nonliving' vaccine candidate for the future.

Serological characterization of guinea pigs infected with H3N2 human influenza or immunized with hemagglutinin protein

BackgroundRecent and previous studies have shown that guinea pigs can be infected with, and transmit, human influenza viruses. Therefore guinea pig may be a useful animal model for better understanding influenza infection and assessing vaccine strategies. To more fully characterize the model, antibody responses following either infection/re-infection with human influenza A/Wyoming/03/2003 H3N2 or immunization with its homologous recombinant hemagglutinin (HA) protein were studied.ResultsSerological samples were collected and tested for anti-HA immunoglobulin by ELISA, antiviral antibodies by hemagglutination inhibition (HI), and recognition of linear epitopes by peptide scanning (PepScan). Animals inoculated with infectious virus demonstrated pronounced viral replication and subsequent serological conversion. Animals either immunized with the homologous HA antigen or infected, showed a relatively rapid rise in antibody titers to the HA glycoprotein in ELISA assays. Antiviral antibodies, measured by HI assay, were detectable after the second inoculation. PepScan data identified both previously recognized and newly defined linear epitopes.ConclusionsInfection and/or recombinant HA immunization of guinea pigs with H3N2 Wyoming influenza virus resulted in a relatively rapid production of viral-specific antibody thus demonstrating the strong immunogenicity of the major viral structural proteins in this animal model for influenza infection. The sensitivity of the immune response supports the utility of the guinea pig as a useful animal model of influenza infection and immunization.

Suspected Needle Stick Transmission of Bartonella vinsonii subspecies berkhoffii to a Veterinarian

Suspected Needle Stick Transmission of Bartonella vinsonii subspecies berkhoffii to a Veterinarian

Different patterns of BK and JC polyomavirus reactivation following renal transplantation

AimReactivation of latent BK polyomavirus (BKV) infection is relatively common following renal transplantation and BKV-associated nephropathy has emerged as a significant complication. JC polyomavirus (JCV) reactivation is less well studied....

Seroconversion and asymptomatic infections during oseltamivir prophylaxis against Influenza A H1N1 2009

BackgroundAnti-viral prophylaxis is used to prevent the transmission of influenza. We studied serological confirmation of 2009 Influenza A (H1N1) infections during oseltamivir prophylaxis and after cessation of prophylaxis.MethodsBetween 22 Jun and 16 Jul 09, we performed a cohort study in 3 outbreaks in the Singapore military where post-exposure oseltamivir ring chemoprophylaxis (75 mg daily for 10 days) was administered. The entire cohort was screened by RT-PCR (with HA gene primers) using nasopharyngeal swabs three times a week. Three blood samples were taken for haemagglutination inhibition testing - at the start of outbreak, 2 weeks after completion of 10 day oseltamivir prophylaxis, and 3 weeks after the pandemic's peak in Singapore. Questionnaires were also administered to collect clinical symptoms.Results237 personnel were included for analysis. The overall infection rate of 2009 Influenza A (H1N1) during the three outbreaks was 11.4% (27/237). This included 11 index cases and 16 personnel (7.1%) who developed four-fold or higher rise in antibody titres during oseltamivir prophylaxis. Of these 16 personnel, 8 (3.5%) were symptomatic while the remaining 8 personnel (3.5%) were asymptomatic and tested negative on PCR. Post-cessation of prophylaxis, an additional 23 (12.1%) seroconverted. There was no significant difference in mean fold-rise in GMT between those who seroconverted during and post-prophylaxis (11.3 vs 11.7, p = 0.888). No allergic, neuropsychiatric or other severe side-effects were noted.ConclusionsPost-exposure oseltamivir prophylaxis reduced the rate of infection during outbreaks, and did not substantially increase subsequent infection rates upon cessation. Asymptomatic infections occur during prophylaxis, which may confer protection against future infection. Post-exposure prophylaxis is effective as a measure in mitigating pandemic influenza outbreaks.

Pandemic (H1N1) 2009 Risk for Nurses after Trivalent Vaccination

To the Editor: We report results of the effect of inactivated seasonal influenza vaccination on risk of pandemic (H1N1) 2009 in a cohort of nurses in Canada who participated in a recent randomized controlled trial that compared the effectiveness of surgical masks with that of N95 respirators in preventing influenza (1). From September 23, 2008, through December 8, 2008, a total of 446 nurses from 8 hospitals in the province of Ontario were enrolled. They were then randomly assigned an intervention; 225 were assigned to wear surgical masks, and 221 were assigned to wear the N95 respirator. The mean age of participants was 36.2 years; 94% were women. A total of 128 (30.3%) received the trivalent influenza vaccine. Vaccination status was similar between the groups: 68 (30.2%) persons in the surgical mask group and 62 (28.1%) persons in the N95 respirator group had received the 2008–2009 trivalent inactivated influenza vaccine. The nurses were monitored from January 12, 2009, through April 23, 2009. Blood specimens for serologic analysis were obtained before enrollment and at the end of the follow-up period. End-of-study serum samples were collected from April 23 through May 15, 2009. Serologic infection was defined by a >4-fold increase in influenza-specific hemagglutinin inhibition assay titer between baseline and convalescent-phase serum samples by using turkey erythrocytes and A/TN/1560/2009(H1N1), a representative pandemic influenza virus. Of the 422 nurses included in the analysis, 42 (10.0%) showed seroconversion to pandemic (H1N1) 2009. Of 128 nurses who received the trivalent influenza vaccine, 9 (7.0%) showed seroconversion vs. 33 (11.2%) of those that did not (relative risk 0.63, 95% confidence interval 0.31–1.27, p = 0.19). Although the point estimate was protective, the confidence interval is wide and does not exclude an increase in risk. Our sample size limits inferences that can be drawn. Heterotypic antibodies may have contributed to the relatively high rate of seroconversion. A rise in antibody titer is considered by some as an outcome associated with bias, unlike virus identification. Nevertheless, these data suggest a possible positive effect of seasonal influenza vaccine reducing risk of infection with pandemic (H1N1) 2009.

Cytomegalovirus Infection in Pregnancy

ObjectivesTo review the principles of prenatal diagnosis of congenital cytomegalovirus (CMV) infection and to describe the outcomes of the affected pregnancies. OutcomesEffective management of fetal infection following primary and secondary maternal CMV infection during pregnancy. Neonatal signs include intrauterine growth restriction (IUGR), microcephaly, hepatosplenomegaly, petechiae, jaundice, chorioretinitis, thrombocytopenia and anemia, and long-term sequelae consist of sensorineural hearing loss, mental retardation, delay of psychomotor development, and visual impairment. These guidelines provide a framework for diagnosis and management of suspected CMV infections. EvidenceMedline was searched for articles published in English from 1966 to 2009, using appropriate controlled vocabulary (congenital CMV infection) and key words (intrauterine growth restriction, microcephaly). Results were restricted to systematic reviews, randomized controlled trials/controlled clinical trials, and observational studies. Searches were updated on a regular basis and incorporated into the guideline. Grey (unpublished) literature was identified through searching the websites of health technology assessment and health technology assessment-related agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies. RecommendationsThe quality of evidence reported in this document has been assessed using the evaluation of evidence criteria in the Report of the Canadian Task Force on Preventive Health Care (Table 1).1.Diagnosis of primary maternal cytomegalovirus (CMV) infection in pregnancy should be based on de-novo appearance of virus-specific IgG in the serum of a pregnant woman who was previously seronegative, or on detection of specific IgM antibody associated with low IgG avidity. (II-2A)2.In case of primary maternal infection, parents should be informed about a 30% to 40% risk for intrauterine transmission and fetal infection, and a risk of 20% to 25% for development of sequelae postnatally if the fetus is infected. (II-2A)3.The prenatal diagnosis of fetal CMV infection should be based on amniocentesis, which should be done at least 7 weeks after presumed time of maternal infection and after 21 weeks of gestation. This interval is important because it takes 5 to 7 weeks following fetal infection and subsequent replication of the virus in the kidney for a detectable quantity of the virus to be secreted to the amniotic fluid. (II-2A)4.The diagnosis of secondary infection should be based on a significant rise of IgG antibody titre with or without the presence of IgM and high IgG avidity. In cases of proven secondary infection, amniocentesis may be considered, but the risk–benefit ratio is different because of the low transmission rate. (III-C)5.Following a diagnosis of fetal CMV infection, serial ultrasound examinations should be performed every 2 to 4 weeks to detect sonographic abnormalities, which may aid in determining the prognosis of the fetus, although it is important to be aware that the absence of sonographic findings does not guarantee a normal outcome. (II-2B)6.Quantitative determination of CMV DNA in the amniotic fluid may assist in predicting the fetal outcome. (II-3B)7.Routine screening of pregnant women for CMV by serology testing is currently not recommended. (III-B)8.Serologic testing for CMV may be considered for women who develop influenza-like illness during pregnancy or following detection of sonographic findings suggestive of CMV infection. (III-B)9.Seronegative health care and child care workers may be offered serologic monitoring during pregnancy. Monitoring may also be considered for seronegative pregnant women who have a young child in day care. (III-B)

Bartonellaspp. Infections, Thailand

<i>Bartonella</i>spp. Infections, Thailand

High Rate of Failure in Treatment of Imported Schistosomiasis

There is an increasing number of imported cases of schistosomiasis in Europe, but there are only few studies on the efficacy of praziquantel for the treatment of schistosomiasis in non-endemic settings. Patients treated for schistosomiasis in 2003 to 2008 were offered reexamination with serology, eosinophil count, IgE, microscopy of 24 h urine samples and/or rectal biopsies >3 months after treatment. All patients had been treated with at least one dose of praziquantel 40 to 60 mg/kg >12 weeks after exposure and had not been reexposed to schistosomiasis after treatment. Twenty-eight traveler (15 tourists and 13 expatriates) and two immigrants were reexamined after treatment. Viable ova were detected in six traveler (20%). Ova were found in 5/23 (22%) rectal biopsies and in 2/12 (17%) urine samples. Treatment failure was suspected in a symptomatic patient who 2 years after treatment had eightfold rise in antibody titer and elevated IgE but no detectable ova in urine or rectal biopsies. Additional 13 patients had one or more parameters, which could indicate persistent infection. There were no significant differences in eosinophil count, IgE or, change in antibody titer between patients with versus without detectable ova after treatment. In traveler with a low parasite burden, assessment of treatment results can be difficult because of the low sensitivity of microscopy and persistence of antibodies for several years after treatment. We found a high rate of treatment failure among traveler, indicating that nonimmune patients may need more than the recommended single day of treatment for eradication of parasites. Until more sensitive and specific methods for detection of persistent, active infection are available, repeated treatment should be considered in patients with continuous symptoms or other indications of treatment failure even when viable ova cannot be detected by microscopy.

Cardiac Tamponade in a Patient With Dengue Fever and Lupus Nephritis: A Case Report

Cases of small pericardial effusion have been reported in association with dengue fever (DF), largely with dengue hemorrhagic fever during epidemic outbreaks. However, cardiac tamponade developed by a patient with DF has not yet been reported in the English literature. We report a case of cardiac tamponade in a patient with DF and lupus nephritis. We describe the characteristic features to differentiate pericardial effusion of lupus origin from that of viral etiology. A 59-year-old Hispanic woman presented to the emergency department with complaints of 5 to 6 days of fever, myalgia, headache, and retro-orbital pain. Her symptoms started 3 days after returning from the Dominican Republic, where a dengue outbreak was reported. Her past medical history was significant for hypertension and lupus nephritis diagnosed 3 months earlier. On day 2, patient developed a large pericardial effusion that progressed to tamponade over the next 2 days, requiring surgical drainage. Subsequently, the patient improved; however, serological analysis did not suggest any lupus flare-up. Pericardial fluid analysis showed hypocellularity without lupus erythematosus cell and biopsy revealed only reactive mesothelial cells suggestive of viral etiology. Dengue serology was reported as markedly elevated, supporting a diagnosis of classic DF (both immunoglobulin M [IgM] titer 2.93 and IgG titer 12.13 by enzyme-linked immunosorbent assay [ELISA]; reference range: <0.90 for both). Absence of rise in serum antinuclear antibody (ANA) titer correlated with lack of inflammatory changes on the pericardium favored viral etiology over lupus origin. This differentiation is pertinent from a management perspective.

Seasonal influenza risk in hospital healthcare workers is more strongly associated with household than occupational exposures: results from a prospective cohort study in Berlin, Germany, 2006/07.

BackgroundInfluenza immunisation for healthcare workers is encouraged to protect their often vulnerable patients but also due to a perceived higher risk for influenza. We aimed to compare the risk of influenza infection in healthcare workers in acute hospital care with that in non-healthcare workers over the same season.MethodsWe conducted a prospective, multicentre cohort study during the 2006/07 influenza season in Berlin, Germany. Recruited participants gave serum samples before and after the season, and completed questionnaires to determine their relevant exposures and possible confounding factors. The main outcome measure was serologically confirmed influenza infection (SCII), defined as a fourfold or greater rise in haemagglutination inhibition antibody titres to a circulating strain of influenza (with post-season titre at least 1:40).Weekly mobile phone text messages were used to prompt participants to report respiratory illnesses during the influenza season. A logistic regression model was used to assess the influence of potential risk factors.ResultsWe recruited 250 hospital healthcare workers (mean age 35.7 years) and 486 non-healthcare workers (mean age 39.2 years) from administrative centres, blood donors and colleges.Overall SCII attack rate was 10.6%. Being a healthcare worker was not a risk factor for SCII (relative risk 1.1, p = 0.70). The final multivariate model had three significant factors: living with children (odds ratio [OR] 3.7, p = 0.005), immunization (OR 0.50, p = 0.02), and - among persons living in households without children - ownership of a car (OR 3.0, p = 0.02). Living with three or more children (OR 13.8, p < 0.01) was a greater risk than living with one or two children (OR 5.3, p = 0.02). 30% of participants with SCII reported no respiratory illness. Healthcare workers were at slightly higher risk of reporting any respiratory infection than controls (adjusted OR 1.3, p = 0.04, n = 850).ConclusionsOur results suggest that healthcare workers in hospitals do not have a higher risk of influenza than non-healthcare workers, although their risk of any respiratory infection is slightly raised. Household contacts seem to be more important than exposure to patients. Car ownership is a surprise finding which needs further exploration. Asymptomatic infections are common, accounting for around a third of serologically confirmed infections.

Reactive macrophage activation syndrome in a patient with parvovirus B19 infection, lymphocytic lichenoid vasculitis, urticaria and angioedema.

47-year-old woman had a history of episodic acute intermittent angioedema and urticaria with moderate pruritus for one month. She was on 10 mg of loratadine daily. She had a fever of 39oC, arthralgia, fatigue, and angioedema of the upper respiratory tract. Laboratory results are shown in [Table 1]. She had elevated IgE (206 kU/L). The immunoassay for C1-esterase inhibitor was normal. She was treated with H1- and H2-blocking antihistamines, and methylprednisolone intravenously (1 mg/kg/day). Culture results and viral titers were negative except for a high positive titer of specific IgG antibody to parvovirus B19 of 11.1 (positive titer >1). On the third week of hospitalization, she deteriorated rapidly and developed a macular rash on the trunk and extremities with generalised lymphadenpathy, liver dysfunction and disseminated intravascular coagulopathy (DIC) [Figure 1]. A skin biopsy specimen was compatible with lymphocytic lichenoid vasculitis. An inflammatory pattern centered on the basal layer of the epidermis and upper dermis in a dense band-like distribution. Direct immunofluorescence showed no IgG, IgA, IgM, C3, C1q and fibrinogen deposits. A bone marrow aspirate showed hemophagocytosis [Figure 2]. Parvovirus B19 DNA was detected by the polymerase chain reaction (PCR) in bone marrow [Figure 3]. Macrophage activation syndrome was confirmed. The patient was treated with methylprednisolone 250 mg/day intravenously and intravenous immunoglobulin (IVIG) 0.55 g/kg BW/day for five consecutive days, followed by methylprednisolone 1 mg/kg daily. Fresh frozen plasma and enoxaparin were administered. Two days after treatment, she improved. Monthly infusions of IVIG were continued for 6 months. Corticosteroids were tapered gradually to 8 mg of methylprednisolone daily. On periodic follow-up, the patient was quite well without episodes of angioedema and no new skin lesions were seen. Our patient met all criteria for reactive macrophage activation syndrome (rMAS) outlined by Imashuku. [1] Acute parvovirus B19 infection can be diagnosed by demonstrating a four-fold rise in serum B19-specific IgG antibody titers, as in our case. B19 specific DNA or antigens can be detected for months or even years after infection. [2], [3] We speculate that the presence of acute parvovirus B19 infection was a trigger for rMAS. [4] Lymphocytic vasculitis is a reactive process. [5], [6] Purpura pigmentosa chronica, fixed drug eruption, urticarial vasculitis, allergic vasculitis, and the vasculitis of Sjogren syndrome are known to have lymphocytic vasculitis. We conclude that rMAS might represent a subgroup of patients with systemic inflammatory response amenable to IVIG treatment. Given early, IVIG may interrupt the processes that lead to macrophage overactivation.

Immune responses and expression profiles of some immune-related genes in Indian major carp, Labeo rohita to Edwardsiella tarda infection

Edwardsiella tarda is an important Gram-negative bacterium that causes systemic infections in a wide range of hosts including fish. The pathogenic mechanisms in this disease are still poorly understood in fish. Indian major carp, Labeo rohita were intraperitoneally challenged with a pathogenic isolate of E. tarda to measure sequential changes in immunity level. A significant decrease in the superoxide production, myeloperoxidase, alternative complement activity, total protein levels and antiprotease activity of serum was marked in the infected fish. However, the serum lysozyme activity and haemagglutination titre were raised in the infected fish. Similarly, a significant rise in specific antibody titre was noticed on and after 10 days post-challenge. This study also elucidates the changes in the relative expression of some immune-related genes viz., interleukin 1-beta (IL-1β), inducible nitric oxide synthase (iNOS), complement component C3, β 2-microglobulin, CXCa, tumor necrosis factor-alpha (TNFα), and C-type and G-type lysozymes during the infection. Significant up-regulation of IL-1β, iNOS, C3, CXCa and expression of both types of lysozyme genes was noticed at 6–12 h post-challenge (h.p.c.) whereas down-regulation of β 2-microglobulin and TNFα genes was observed after 48 h p.c. The results obtained here strengthen the understanding on molecular pathogenesis of edwardsiellosis in L. rohita.

Equine influenza outbreak in India (2008–09): Virus isolation, sero-epidemiology and phylogenetic analysis of HA gene

An outbreak of equine influenza (EI) was reported in India in June, 2008 after a gap of two decades. The outbreak started from Jammu and Kashmir (Katra), northern state of India and spread to the other parts of the country affecting equines in 11 states. The virus (H3N8) was isolated from nasal swabs obtained from clinical cases in various locations in the country including Katra (Jammu and Kashmir), Mysore (Karnataka) and Ahmedabad (Gujarat) using embryonated chicken eggs. The virus isolates were identified as H3N8 by haemagglutination inhibition (HI) test titration with standard serum and by sequencing of full-length haemagglutinin (HA) gene and partial sequence of neuraminidase (NA) gene. Paired serum samples ( n = 271) showing more than fourfold rise in antibody titres tested from 11 states confirmed equine influenza. Serum samples ( n = 2517) of equines from 13 states of the country screened by HI test revealed 687 (26.85%) samples positive for antibodies to EI (H3N8). Phylogenetic analysis of the haemagglutinin (HA) gene confirmed the virus to be closely related to Clade 2 of the Florida sublineage in American lineage. Comparison of deduced amino acid sequence of HA gene with EIV isolates from various lineages showed substitutions in the antigenic regions C and D. HA1 gene sequence had highest amino acid identity to A/eq/Gansu/7/08 and A/eq/Hubei/6/08 isolates from China and Inner-Mongolia isolate, while the complete HA gene sequence was closest to A/eq/A/eq/Newmarket/5/03, A/eq/Bari/05 and A/eq/Kentucky/05/02 isolates. Recent outbreaks of Mongolia, China and India by clade 2 EI viruses imply their predominance in Asia in addition to Europe.

Efficacy of a Replikin Peptide Vaccine Against Low-Pathogenicity Avian Influenza H5 Virus

In this study, the sequence of the H5 and PB1 genes of the low-pathogenic avian influenza virus (LPAI) A/Black Duck/NC/674-964/06 isolate were determined for replikin peptides and used to design and chemically synthesize a vaccine. The vaccine was used to immunize specific-pathogen-free (SPF) leghorn chickens held in Horsfall isolation units, by the upper respiratory route, at 1, 7, and 14 days of age. The birds were challenged at 28 days of age with 1 x 10(6) 50% embryo infective dose of the LPAI Black Duck/NC/674-964/06 H5N1 virus per bird. Oropharyngeal and cloacal swabs were collected at 2, 4, and 7 days postinoculation (PI) for virus detection by real-time RT-PCR. Serum was collected at 7, 14, and 21 days PI and examined for antibodies against avian influenza virus by the enzyme-linked immunosorbent assay and hemagglutination inhibition (HI) tests. Tissue samples for histopathology were collected from three birds per group at 3 days PI. The experimental design consisted of a negative control group (not vaccinated and not challenged) and a vaccinated group, a vaccinated and challenged group, and a positive control group (challenged only). None of the nonchallenged birds, the vaccinated birds, or the vaccinated and challenged birds showed overt clinical signs of disease during the study. A slight depression was observed in the nonvaccinated challenged birds on day 2 postchallenge. Although the numbers of birds per group are small, no shedding of the challenge virus was detected in the vaccinated and challenged birds, whereas oropharyngeal and cloacal shedding was detected in the nonvaccinated and challenged birds. HI antibodies were detected in the vaccinated and nonchallenged group as well as in the vaccinated and challenged group, but rising antibody titers, indicating infection with the LPAI challenge virus, were not detected. Rising HI titers were observed in the nonvaccinated and challenged group. In addition, no antibodies were detected in the nonchallenged birds. Noteworthy microscopic lesions were not observed in the vaccinated and challenged birds, whereas nonvaccinated-challenged birds had microscopic lesions consistent with infection with LPAI viruses. Taken together, these data indicate that a replikin peptide vaccine, specifically made against the H5N1 Black Duck/NC/674-964/06 isolate, and administered three times to the upper respiratory tract, was capable of protecting chickens from infection and from shedding of the homologous virus, which is extremely important because reduced virus shedding and transmission decreases the potential for H5 LPAI viruses to become HPAI viruses. The study is also important because it shows that the vaccine can be effectively mass-delivered to the upper respiratory tract.

Systemic, nasal and oral live vaccines against Pseudomonas aeruginosa: A clinical trial of immunogenicity in lower airways of human volunteers

Vaccination against Pseudomonas aeruginosa is a desirable, yet challenging strategy for prevention of airway infection in patients with cystic fibrosis. We compared the formation of antibodies in lower airways induced by systemic and mucosal vaccination strategies. We immunised 48 volunteers in six vaccination groups with either a systemic, a nasal, or four newly constructed oral live vaccines based on attenuated live Salmonella (strains CVD908 and Ty21a), followed by a systemic booster vaccination. All vaccines were based on a recombinant fusion protein of the highly conserved P. aeruginosa outer membrane proteins OprF and OprI as antigen. While systemic and mucosal vaccines induced a comparable rise of serum antibody titers, a significant rise of IgA and IgG antibodies in the lower airways was noted only after nasal and oral vaccinations. We conclude that nasal and oral OprF-OprI vaccines are promising candidates for development of antipseudomonal immunisation through inducing a specific antibody response in the lung.

A Curious Case of Anti-D Antibody Titer

RhD alloimmunization remains a threat to 1% of the 10% of RhD-negative women in the United States who are giving birth to RhD-positive fetuses despite routine antenatal and postpartum administration of Rh(o)D immune globulin (RhIG). This report examines the clinical course of an RhD-negative woman who developed a high anti-D antibody titer during her pregnancy while carrying an RhD-positive female fetus yet had a negative antibody screen at the time she gave birth. Although she delivered a healthy newborn unaffected by hemolytic disease, subsequent pregnancies will be treated as though she is RhD alloimmunized. The discussion below includes possible causes for the abrupt rise in this woman's anti-D antibody titer, a review of the complex Rh system and cellular anamnestic response, and current fetal surveillance for hemolytic disease of the fetus and newborn.

Immune responses against recombinant tick antigen, Bm95, for the control of Rhipicephalus ( Boophilus) microplus ticks in cattle

Immune responses against Bm95 recombinant cattle tick antigen and its protective efficacy for control of Rhipicephalus ( Boophilus) microplus ticks were determined in experimental crossbred cow calves. Anti-Bm95 antibody titers, as assessed by indirect ELISA, in immunized calves ranged from 196.1 ± 13.7 on day 0 to 7979.9 ± 312.5 on day 110 post-primary immunization. The rise in antibody titer was statistically significant ( p < 0.01) throughout the study period. Besides this, constantly higher lymphoproliferative response (LPR), as assessed by lymphocyte stimulation test, was observed from 10 days post-immunization, but a positive LPR of antigen stimulated cells in immunized animals was recorded only on day 50 and day 70 post-immunization. Following challenge of immunized calves with larvae of R. microplus, significant increase ( p < 0.01) in rejection percentage, mean number of damaged ticks, mean percentage of dead ticks, and decrease in engorgement weight were recorded in immunized animals. Also, there were significant differences ( p < 0.01) in preoviposition period, oviposition period, egg mass weight and percent hatchability between the immunized and control calves. The percent reduction in number of adult females in vaccinated calves, reduction in mean weight of egg masses, percent reduction in mean weight and reduction in fertility of engorged females collected from vaccinated calves were determined and the efficacy of Bm95 recombinant cattle tick antigen was 81.27%.

Rapid Increase of Scrub Typhus, South Korea, 2001–2006

Rapid Increase of Scrub Typhus, South Korea, 2001–2006

Standardization and validation of Vero cell assay for potency estimation of diphtheria antitoxin serum

Diphtheria toxin has the capacity to block protein synthesis in cultured mammalian cells, and thus causing cell death. This capacity of diphtheria toxin was utilized for in-vitro neutralization test to determine antibody titer, using Vero cells, which have been found to be susceptible to diphtheria toxin. In the present study, a Vero cell assay was standardized and validated for potency estimation of diphtheria antitoxin serum (DATS). The results obtained by Vero cell assay were compared with in-vivo biological assay. High degree of correlation (+0.98) was found between in-vivo biological assay and in-vitro Vero cell assay. The assay has also been found to be effective in determining the rising antibody titer in the equines inducted in DATS production. The present study indicated that although biological assays hold the key for final potency estimations till date but in the future scenario in-vitro Vero cell assay may be a good alternative to in-vivo biological assay.