BackgroundEarly life microbiota is an important determinant of immune and metabolic development and may have lasting consequences. The maternal gut microbiota during pregnancy or breastfeeding is important for defining infant gut microbiota. We hypothesized that maternal gut microbiota during pregnancy and breastfeeding is a critical determinant of infant immunity. To test this, pregnant BALB/c dams were fed vancomycin for 5 days prior to delivery (gestation; Mg), 14 days postpartum during nursing (Mn), or during gestation and nursing (Mgn), or no vancomycin (Mc). We analyzed adaptive immunity and gut microbiota in dams and pups at various times after delivery.ResultsIn addition to direct alterations to maternal gut microbial composition, pup gut microbiota displayed lower α-diversity and distinct community clusters according to timing of maternal vancomycin. Vancomycin was undetectable in maternal and offspring sera, therefore the observed changes in the microbiota of stomach contents (as a proxy for breastmilk) and pup gut signify an indirect mechanism through which maternal intestinal microbiota influences extra-intestinal and neonatal commensal colonization. These effects on microbiota influenced both maternal and offspring immunity. Maternal immunity was altered, as demonstrated by significantly higher levels of both total IgG and IgM in Mgn and Mn breastmilk when compared to Mc. In pups, lymphocyte numbers in the spleens of Pg and Pn were significantly increased compared to Pc. This increase in cellularity was in part attributable to elevated numbers of both CD4+ T cells and B cells, most notable Follicular B cells.ConclusionOur results indicate that perturbations to maternal gut microbiota dictate neonatal adaptive immunity.Electronic supplementary materialThe online version of this article (10.1186/s40168-018-0511-7) contains supplementary material, which is available to authorized users.

Microbiota from various maternal sites, including the gut, vagina and breast milk, are known to influence colonization in infants. However, emerging evidence suggests that these sites may exert their influence prior to delivery, in turn influencing fetal immune development. The dogma of a sterile womb continues to be challenged. Regardless, there is convincing evidence that the composition of the maternal gut prior to delivery influences neonatal immunity. Therefore, while the presence and function of placental microbiome is not clear, there is consensus that the gut microbiota during pregnancy is a critical determinant of offspring health. Data supporting the notion of bacterial translocation from the maternal gut to extra-intestinal sites during pregnancy are emerging, and potentially explain the presence of bacteria in breast milk. Much evidence suggests that the maternal gut microbiota during pregnancy potentially determines the development of atopy and autoimmune phenotypes in offspring. Here, we highlight the role of the maternal microbiota prior to delivery on infant immunity and predisposition to diseases. Moreover, we discuss potential mechanisms that underlie this phenomenon.

Maternal immune transfer is the most significant source of protection from early-life infection, but whether maternal transfer of immunity by nursing permanently alters offspring immunity is poorly understood. Here, we identify maternal immune imprinting of offspring nursed by mothers who had a pre-conception helminth infection. Nursing of pups by helminth-exposed mothers transferred protective cellular immunity to these offspring against helminth infection. Enhanced control of infection was not dependent on maternal antibody. Protection associated with systemic development of protective type 2 immunity in T helper 2 (TH2) impaired IL-4Rα−/− offspring. This maternally acquired immunity was maintained into maturity and required transfer (via nursing) to the offspring of maternally derived TH2-competent CD4 T cells. Our data therefore reveal that maternal exposure to a globally prevalent source of infection before pregnancy provides long-term nursing-acquired immune benefits to offspring mediated by maternally derived pathogen-experienced lymphocytes.

BackgroundNew reagents have emerged allowing researchers to assess a growing number of vaccine-associated immune parameters. Multiplex immunoassay(s) are emerging as efficient high-throughput assays in malaria serology. Currently, commercial vendors market several bead reagents for cytometric bead assays (CBA) but relative performances are not well published. We have compared two types of bead-based multiplex assays to measure relative antibody levels to malarial antigens.MethodsAssays for the measurement of antibodies to five Plasmodium falciparum vaccine candidates using non-magnetic and magnetic fluorescent microspheres were compared for their performances with a Bio-Plex200 instrument. Mean fluorescence intensity (MFI) was determined from individuals from western Kenya and compared to known positive and negative control plasma samples.ResultsP. falciparum recombinant antigens were successfully coupled to both non-magnetic and magnetic beads in multiplex assays. MFIs between the two bead types were comparable for all antigens tested. Bead recovery was superior with magnetic beads for all antigens. MFI values of stored non-magnetic coupled beads did not differ from freshly coupled beads, though they showed higher levels of bead aggregation.DiscussionMagnetic and non-magnetic beads performed similarly in P. falciparum antibody assays. Magnetic beads were more expensive, but had higher bead recovery, were more convenient to use, and provided rapid and easy protocol manipulation. Magnetic beads are a suitable alternative to non-magnetic beads in malarial antibody serology.

Both maternal microbiota and helminth infection may alter offspring immunity but the relationship between these is underexplored. We hypothesized that maternal helminth exposure prior to pregnancy has lasting consequences on offspring intestinal microbiota and consequent immunity. Female BALB/c adult mice were infected with 500L3 Nippostrongylus brasiliensis (N brasiliensis). Infection was cleared by ivermectin treatment, and mice were mated 3 weeks post‐infection (NbM). Control mice were not infected but were exposed to ivermectin (NvM). We analysed maternal gut microbiota during pregnancy, breastmilk microbiota and offspring faecal microbiota and immunity 2 weeks after delivery. During pregnancy, NbM (Mothers previously infected with Nippostrongylus brasiliensis) displayed significantly altered stool bacterial communities (R2 = .242; P = .001), with increased abundance of Enterococcaceae versus NvM (Naive mothers). Similarly, we observed a profound impact on breastmilk microbiota in NbM vs NvM. Moreover, NbM pups showed significantly altered gut microbial communities at 14 days of age versus those born to NvM with increased relative abundance of Coriobacteriaceae and Micrococcaceae. These changes were associated with alterations in pup immunity including increased frequencies and numbers of activated CD4 T cells (CD4 + CD44hi) in NbM offspring spleens. Taken together, we show that preconception helminth infections impact offspring immunity possibly through alteration of maternal and offspring microbiota.

No abstract

Background: HIV-1 drug resistance (HIVDR) assays are critical components of HIV clinical management programs in the face of emerging drug resistance. However, the high costs associated with existing commercial HIVDR assays prohibit their routine usage in resource-limited settings. We present the performance characteristics of a modified commercial HIVDR testing assay. Methods: A total of 26 plasma samples were used to validate and assess the accuracy, precision, reproducibility and amplification sensitivity of a modified HIVDR assay by HIV genotyping. In addition, a cost comparison between the original and the modified assay was performed using the ingredient costing approach. Results: The performance characteristics of the modified assay were in agreement with the original assay. Accuracy, precision and reproducibility showed nucleotide sequence identity of 98.5% (confidence interval (CI), 97.9–99.1%), 98.67% (CI, 98.1–99.23) and 98.7% (CI, 98.1–99.3), respectively.  There was no difference in the type of mutations detected by the two assays (χ 2 = 2.36, p = 0.26). Precision and reproducibility showed significant mutation agreement between replicates (kappa = 0.79 and 0.78), respectively ( p < 0.05). The amplification sensitivity of the modified assay was 100% and 62.5% for viremia ≥1000 copies/ml and <1000 copies/ml respectively. Our assay modification translates to a 39.2% reduction in the cost of reagents. Conclusions: Our findings underscore the potential of modifying commercially available HIVDR testing assays into cost-effective, yet accurate assays for use in resource-limited settings.

The composition of the pioneer microbiota that colonize the infant gut are determined by the mother. Polymyxin B-induced changes in the maternal microbiota during pregnancy impact the offspring gut microbiota but not vaccine-specific CD4 T cell response. However, when infected with Mycobacterium tuberculosis , offspring born to mothers with an altered gut microbiota are susceptible to infection compared to those born to mothers not exposed to antibiotics.