The effect of maternal antibodies on the cellular immune response after infant vaccination: A review

During the last few decades, maternal immunization as a strategy to protect young infants from infectious diseases has been increasingly recommended, yet some issues have emerged. Studies have shown that for several vaccines, such as live attenuated, toxoid and conjugated vaccines, high maternal antibody titers inhibit the infant’s humoral immune response after infant vaccination. However, it is not clear whether this decreased antibody titer has any clinical impact on the infant’s protection, as the cellular immune responses are often equally important in providing disease protection and may therefore compensate for diminished antibody levels. Reports describing the effect of maternal antibodies on the cellular immune response after infant vaccination are scarce, probably because such studies are expensive, labor intensive and utilize poorly standardized laboratory techniques. Therefore, this review aims to shed light on what is currently known about the cellular immune responses after infant vaccination in the presence of high (maternal) antibody titers both in animal and human studies. Overall, the findings suggest that maternally derived antibodies do not interfere with the cellular immune responses after infant vaccination. However, more research in humans is clearly needed, as most data originate from animal studies.     

A 16-year review of seroprevalence studies on measles and rubella

The determination of the seroprevalence of vaccine-preventable diseases is critical in monitoring the efficacy of vaccination programmes and to assess the gaps in population immunity but requires extensive organisation and is time and resource intensive. The results of the studies are frequently reported in peer-reviewed scientific, government and non-government publications. A review of scientific literature was undertaken to advise the development of WHO guidelines for the assessment of measles and rubella seroprevalence. A search of the National Library of Medicine’s PubMed online publications using key words of ‘measles’, ‘rubella’, combined with ‘serosurvey’, ‘seroprevalence’, ‘immunity’ and ‘population immunity’ was conducted. A total of 97 articles published between January 1998 and June 2014 were retrieved, 68 describing serosurveys for measles and 58 serosurveys for rubella, conducted in 37 and 36 different countries respectively. Only 13 (19%) and 8 (14%) respectively were UN classified “least developed countries”. The study sample varied markedly and included combinations of male and female infants, children, adolescents and adults. The study sizes also varied with 28% and 33% of measles and rubella studies respectively, having greater than 2000 participants. Microtitre plate enzyme immunoassays were used in 52 (76%) measles studies and 40 (69%) rubella studies. A total of 39 (57%) measles and 44 (76%) rubella studies reported quantitative test results. Seroprevalence ranged from 60.8% to 95.9% for measles and 53.0% to 99.3% for rubella studies. The review highlighted that infants lost maternally-acquired immunity within 9 months of birth and were unprotected until vaccination. Two groups at higher risk of infection were identified: young adults between the ages of 15 and 30 years and immigrants.     

Identification of B cell epitopes of Per a 5 allergen using bioinformatic approach

BackgroundImmune epitopes of allergens are pivotal for development of novel diagnostic and therapeutic modalities. Present study aims to identify antigenic determinants of Per a 5, a clinically relevant cross reactive cockroach allergen.MethodsThe three dimensional structure of Per a 5 was modelled using Modeller 9v11 software. A combination of sequence and structure based computational tools were employed for predicting B cell epitopes. Epitopes were synthesized and immunoreactivity was assessed by ELISA using cockroach hypersensitive patient’s sera. Cross-reactivity potential of predicted epitopes was assessed with SDAP and ConSurf and validated by IgE ELISA with fungal and mite hypersensitive patient’s sera.ResultsPer a 5 structure exhibited good quality factor in ERRAT and high stereochemical stability. In silico analysis revealed six B cell epitopes (BC-P1 to P6). BC-P3 demonstrated significant IgE binding followed by BC-P2 and BC-P1 with cockroach hypersensitive patient’s sera. Per a 5 epitopes demonstrate considerable similarity with broad spectrum of allergens from fungal, mites, helminths, fruits and nuts. Analysis of PD values indicate BC-P4 to be well conserved among dust mite and helminth GSTs (8.89, 10.63 and 10.69 with D. pteronyssinus, W. bancrofti and F. hepatica respectively). ConSurf analysis of Per a 5 revealed specific enrichment of evolutionarily similar amino acid residues in BC-P2 (with fungal and mite GSTs) and BC-P4 (with mite and helminth GSTs). Further, IgE binding analysis of epitopes demonstrate BC-P2, BC-P3 and BC-P5 as high IgE binders in fungal hypersensitive sera while BC-P1, BC-P2, BC-P4 and BC-P5 demonstrated significant IgE binding with mite hypersensitive sera.ConclusionsAmong the predicted epitopes, BC-P3 demonstrates maximal IgE binding ability. Computational analysis suggests strong evolutionary conservation and cross reactive potential of BC-P4 with allergens in dust mite and helminths. ELISA highlights predictive potential of analysing evolutionarily conserved residues for uncovering potentially cross reactive antigenic determinants.General significanceImmune epitopes of Per a 5 were identified for aiding molecular diagnosis and potential cross reactivity.     

The bane of coastal marine environment: A fatal case of Vibrio vulnificus associated cellulitis and septicaemia

Vibrio vulnificus is a Gram negative motile bacterium known to cause fatal septicaemia and wound infection. It is commonly associated with the consumption of under-cooked seafood or exposure to marine environment. We report a case of a 55 year old male patient, who was presented with right lower limb cellulitis and septicaemia due to V. vulnificus. V. vulnificus infection in India are rare. However, increasing reports of V. vulnificus from India recommends considering the pathogen while dealing necrotising fasciitis especially in the proximity of marine environment.     

Interactions between cancer cells and immune cells drive transitions to mesenchymal-like states in glioblastoma

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Residual survival and local dispersal drive reinfestation by Triatoma dimidiata following insecticide application in Guatemala

Chagas disease is caused by the protozoan parasite Trypanosoma cruzi and transmitted by triatomine insect vectors. In Guatemala, insecticide spraying is an integral part of management of the main vector, Triatoma dimidiata. Spraying typically has low efficacy, which may be due to incomplete elimination from infested houses, within-village dispersal, or influx from other villages or sylvan environments. To evaluate how these mechanisms contribute to reinfestation, we conducted a time-course analysis of T. dimidiata infestation, abundance and household genetic structure in two nearby villages in Jutiapa, Guatemala; houses in the first village were surveyed, treated with insecticide if infested and then re-surveyed at eight and 22 months following spraying, while the second village served as an untreated control to quantify changes associated with seasonal dispersal. Insects were genotyped at 2–3000 SNP loci for kinship and population genetic analyses. Insecticide application reduced overall infestation and abundance, while the untreated village was stable over time. Nevertheless, within two years 35.5% of treated houses were reinfested and genetic diversity had largely recovered. Insects collected from reinfested houses post-spraying were most closely related to pre-spray collections from the same house, suggesting that infestations had not been fully eliminated. Immigration by unrelated insects was also detected within a year of spraying; when it occurred, dispersal was primarily local from neighboring houses. Similar dispersal patterns were observed following the annual dispersal season in the untreated village, with high-infestation houses serving as sources for neighboring homes. Our findings suggest that the efficacy of pyrethroid application is rapidly diminished by both within-house breeding by survivors and annual cycles of among-house movement. Given these patterns, we conclude that house structural improvements, an integral part of the Ecohealth approach that makes houses refractory to vector colonization and persistence, are critical for long-term reduction of T. dimidiata infestation.     

Genetic diversity of HLA system in a population from Guerrero,Mexico

We studied HLA class I (HLA-A, -B) and class II (HLA-DRB1, -DQB1) alleles by PCR-SSP based typing in 144 Mexicans from the state of Guerrero to obtain information regarding allelic and haplotypic frequencies. We find that the ten most frequent haplotypes in the state of Guerrero include eight Native American and two European haplotypes. Admixture estimates revealed that the main genetic components in the state of Guerrero are Native American (61.36 ± 2.69% by ML; 54.17% of Native American haplotypes) and European (35.01 ± 4.59% by ML; 32.29% of European haplotypes), and a relatively low African genetic component (3.63 ± 2.38% by ML; 5.90% of African haplotypes).