Disappearance Of Maternal Antibodies Research Articles

Dynamics of immunoglobulin G subclasses during the first two years of life in Malawian infants born to HIV-positive mothers

BackgroundMaternal antibodies are key components of the protective responses of infants who are unable to produce their own IgG until 6 months of life. There is evidence that HIV-exposed uninfected children (HEU) have IgG levels abnormalities, that can be partially responsible for the higher vulnerability to infections in the first 2 years of the life of this population.This retrospective study aimed to characterize the dynamics in plasma levels of total IgG and their isotypes during the first 2 years of life in HEU infants exclusively breastfed through 6 months of age.MethodsTotal IgG, IgG1, IgG2, IgG3 and IgG4 isotypes, and IgM and IgA plasma concentrations were determined by nephelometric methods in 30 Malawian infants born to HIV-positive women at month 1, 6 and 24 of life.ResultsAt 1-month infants had a median concentration of total IgG of 8.48 g/l, (IQR 7.57–9.15), with an overrepresentation of the IgG1 isotype (89.0% of total) and low levels of IgG2 (0.52 g/l, IQR, 0.46–0.65). Total IgG and IgG1 concentrations were lower at 6 months (− 2.1 and − 1.12 g/dl, respectively) reflecting disappearance of maternal antibodies, but at 24 months their levels were higher with respect to the reported reference values for age-matched pairs. Abnormal isotype distribution was still present at 24 months with IgG2 remaining strongly underrepresented (0.87 g/l, 7.5% of total IgG).ConclusionHIV exposure during pregnancy and breastfeeding seems to influence the IgG maturation and isotype distribution that persist in 2-year old infants.

Prevention of predicted neonatal isoerythrolysis with jaundice foal agglutination test in a newborn foal

This case report aims to highlight the utility of the jaundice foal agglutination (JFA) test used in the prevention of neonatal foal death caused by equine neonatal isoerythrolysis. The colostrum and the serum of a Friesian mare with repeated neonatal foal deaths and the whole blood of her newborn foal were tested for 5 days with the JFA test to detect a probable incompatibility. For the first 2 days, the JFA test gave a significantly positive reaction, indicating the existence of antibodies in the colostrum of the mare against the foal's erythrocyte antigens. The foal was not allowed access to her mother's colostrum and was fed with the frozen colostrum of other mares. At day 5, JFA test results were negative, indicating the disappearance of maternal antibodies from the colostrum.

Hospitalization of newborns and young infants for chickenpox in France

Chickenpox is often considered more severe during the first year of life, but its course is usually mild during the first 3 months of life, presumably owing to the persistence of maternal antibodies. Hospitalization and intravenous acyclovir therapy are generally restricted to severe cases but also systematically recommended in newborns in France, irrespective of the clinical severity of the infection. This recommendation was launched in 1998 when Varicella zoster virus (VZV)-specific immunoglobulins were not available in the country and has remained unchanged since. The aim of this prospective observational study was to describe complications of varicella infection in a population of 745 children hospitalized for varicella before 1 year of age, with a specific focus on newborns. Complications occurred in 65% of cases. They were very rare before the age of 1 month (10%) but their incidence then increased progressively with age and probably the disappearance of maternal antibodies: 42% (1–2 months), 66% (3–5 months), 70% (6–8 months), and 79% (9–12 months). Conclusion Chickenpox is usually mild in newborns because most of them are protected by VZV maternal antibodies. Unless the absence of maternal VZV immunity is demonstrated, newborns with mild chickenpox should not require antiviral therapy.

Neonatal lupus erythematosus: case report and review of the literature

Neonatal lupus erythematosus (NLE) is a disease of the first few months of infancy. It is caused by anti-SSA and anti-SSB antibodies, which are products of maternal autoimmune disorders (SLE, Sjögren, rheumatoid arthritis) and can be passively transported across the placenta. The prevalence of NLE is low. The major clinical findings are cutaneous (typical annular erythematous plaques), cardiac, hepatic and hematologic alterations. Its most severe consequence is third-degree heart block, which is irreversible, requires pacemaker-implantation and responsible for the 20-30% mortality rate. Symptoms usually resolve spontaneously at age of 6-9 months in association with disappearance of maternal antibodies from the infant's serum. In our case the typical cutaneous manifestations covered virtually the whole body, were present at birth, however, no conduction defects developed. The fact that the mother's sickness was not known at birth made it difficult to establish the diagnosis. The significant thrombocytopaenia, progressive skin-changes and the elevated liver function tests necessitated systemic steroid treatment.

Immune Response and Resistance to Infectious Bursal Disease Virus of Chicken Lines Selected for High or Low Antibody Response to Escherichia coli

Two experimental broiler lines were developed by divergent selection for high (HH) and low (LL) antibody response to Escherichia coli. Antibody response of these lines to immunization with a commercial vaccine (whole inactivated virus, WIV) against infectious bursal disease virus (IBDV) or with proteins VP2 and VP3 of that virus, and their resistance to challenge with a virulent IBDV, were tested. The study was performed with 213 male and female chicks from the tenth generation of the HH and LL lines. At 15 d of age, after disappearance of maternal antibodies, chicks from each line were randomly divided into four groups and injected with WIV, VP2, VP3, or adjuvant alone as a negative control. Chicks were bled 18 d postinjection, and antibody titers were determined by ELISA. Ten days later, the chicks were challenged with a virulent strain of the virus and killed after 10 d; the ratio of bursa of Fabricius to 100 g BW was determined for each bird. Significant differences in antibody titers were found among immunized and control chicks. Chicks from the HH line exhibited significantly higher antibody titers than LL chicks in response to WIV and VP2 vaccines but not to VP3 vaccine. Following challenge, bursa weight (relative to BW) of HH and LL chicks vaccinated with WIV and VP2 was significantly higher (P < 0.01) than that of chicks vaccinated with VP3 or the challenged unvaccinated control. No difference was found in this parameter between the latter two groups. Possible explanations for the differences in the line response to VP2 and VP3 are discussed.

Production of bovine herpesvirus type 1-seronegative latent carriers by administration of a live-attenuated vaccine in passively immunized calves.

The consequences of the vaccination of neonatal calves with the widely used live-attenuated temperature-sensitive (ts) bovine herpesvirus type 1 (BHV-1) were investigated. The ts strain established acute and latent infections in all vaccinated calves either with or without passive immunity. Four of seven calves vaccinated under passive immunity became clearly BHV-1 seronegative by different serological tests, as did uninfected control calves after the disappearance of maternal antibodies, and they remained so for long periods. A cell-mediated immune response was detected by a BHV-1 gamma interferon assay, but this test failed to detect the seronegative latent carriers (SNLCs). While they are not detected, SNLCs represent a threat for BHV-1-free herds or countries. This study demonstrates that SNLCs can be easily obtained by inoculation with a live-attenuated BHV-1 under passive immunity and that latent carrier animals without any antibody do exist. Consequently, this situation could represent a good model to experimentally produce SNLCs.

Effects of bovine herpesvirus type 1 infection in calves with maternal antibodies on immune response and virus latency.

The presence of maternally derived antibodies can interfere with the development of an active antibody response to antigen. Infection of seven passively immunized young calves with a virulent strain of bovine herpesvirus type 1 (BHV-1) was performed to determine whether they could become seronegative after the disappearance of maternal antibodies while latently infected with BHV-1. Four uninfected calves were controls. All calves were monitored serologically for 13 to 18 months. In addition, the development of a cell-mediated immune response was assessed by an in vitro antigen-specific gamma interferon (IFN-gamma) production assay. All calves had positive IFN-gamma responses as early as 7 days until at least 10 weeks after infection. However, no antibody rise was observed after infection in the three calves with the highest titers of maternal antibodies. One of the three became seronegative by virus neutralization test at 7 months of age like the control animals. This calf presented negative IFN-gamma results at the same time and was classified seronegative by enzyme-linked immunosorbent assay at around 10 months of age. This calf was latently infected, as proven by virus reexcretion after dexamethasone treatment at the end of the experiment. In conclusion, this study demonstrated that BHV-1-seronegative latent carriers can be obtained experimentally. In addition, the IFN-gamma assay was able to discriminate calves possessing only passively acquired antibodies from those latently infected by BHV-1, but it could not detect seronegative latent carriers. The failure to easily detect such animals presents an epidemiological threat for the control of BHV-1 infection.

Experimental production of congenital persistent swine fever infections: II. Effect on functions of the immune system

Twelve pregnant sows were infected at various stages of gestation with a low-virulent field strain of swine fever (SF) virus. The sows developed neutralizing antibody in serum, colostrum and milk. Only one pig had antibody to SF virus at birth. Twenty-three congenitally infected pigs developed a persistent viraemia. In the plasma samples of these pigs, neither antibodies nor virus-antibody complexes were detected after the disappearance of maternal antibodies. The persistently infected pigs showed a normal antibody response against sheep red blood cells, except in the terminal stage of disease. These observations indicate immunological tolerance to SF virus in these pigs. Immunological tolerance was also induced in pigs which had been infected in utero after the onset of immune competence. The lymphocyte response to phytohaemagglutinin seemed to be slightly depressed in the persistently infected pigs, whereas the response to pokeweed mitogen was comparable with that of control pigs. A clear, cell-mediated immune response to SF virus could not be demonstrated by the lymphocyte stimulation test. Three pigs that were born uninfected did not produce neutralizing antibody following natural exposure from in-contacts, whereas the littermates did. These pigs appeared to be sensitized when challenged with virulent SF virus.

A congenital persistent swine fever infection. II. Immune response to swine fever virus and unrelated antigens

After the disappearance of maternal antibodies, no antibodies were detected in five pigs that were congenitally infected with the Bergen strain of swine fever virus. The pigs lived for 2–11 months. One pig showed low levels of precipitating antibody during the last month of its life. The pigs had a normal immune response to sheep red blood cells and to pig parvovirus. These observations suggest the presence of immunological tolerance to swine fever virus in these pigs. Cell mediated immunity, measured by phytohaemagglutinin lymphocyte stimulation, appeared to be normal.