Neonates immunity

Inject the neonates daily on d 1-5 after birth with 0.05 mL 0.5 mg/ mL of crossreacting antigen into the neck scruff. (The neonatal immune systems are maturing at this time and because the cross-reacting antigen is present they will adopt these proteins as self and lose the ability to mount an immune response to them.)... 

In humans, there are five isotypes of antibodies, IgG, IgA, IgD, IgE, and IgM, which are defined by the structures of their heavy chains and their abilities to form multimers (Figure 10.1) [8], IgG is the most abundant isotype present in serum with average serum concentrations ranging from 0.5 to 9mg/ml depending on the IgG subtype. This is followed by IgA (3mg/ml), IgM (1.5mg/ml), IgE (0.05 mg/ml), and IgD (trace). Each antibody isotype has unique functions. Critical functions of IgG include opsonization, complement activation, antibody-dependent cell-mediated cytotoxicity (ADCC), passive immunity, and regulation of B cells. Both IgM and IgD act as antigen receptors on naive B cells, and soluble, multimeric forms of IgM are involved in complement activation. IgA is involved in mucosal and passive neonatal immunity, while IgE is involved in immediate hypersensitivity [8],... 

Much debate surrounds the use of BCG vaccine, a matter of some importance, considering that TB kills c. 3 million people annually and that drug-resistant strains have emerged. While the vaccine has demonstrated some efficacy in preventing juvenile TB, it has little prophylactic effect against postprimary TB in those already infected. One solution is to bring forward the BCG immunization to include neonates. Immunization at 2-4 weeks of age will ensure that immunization precedes infection,... 

Proper development of immune tolerance is necessary for the maintenance of gut homeostasis and an efficient response against pathogens. Dysregulation of the involved mechanisms can lead to inappropriate intestinal inflammation against microbiota, such as inflammatory bowel disease. The immaturity of the neonatal immune system explains the age-dependent differences of the immune responses against pathogens and the susceptibility to different types of infection (Tourneur and Chassin 2013). 

Tourneur, E. and C. Chassin (2013). "Neonatal immune adaptation of the gut and its role during infections." Clin. Dev. Immtmol 2013 270301. 

Cord blood is used as an alternative source of hemopoietic stem cells, with the potential advantage that it has less-stringent requirements for HLA matching than hematopoietic stem cells from an adult unrelated donor. Because the neonatal immune system is naive, transplantation of cord blood stem cells yields a lower incidence of acute and chronic GVHD [99 100 =,101 =,102 =,103, 104 ]. The low expression of co-stimulatory molecules on cord blood stem cells could contribute to the lower risk of rejection by the immune system compared with bone marrow transplantation [99 ]. A potential disadvantage of cord blood stem cells is that immune reconstitution is substantially delayed compared with bone marrow transplantation, making recipients more susceptible to... 

When a mminant is bom, it consumes colostmm within a few hours. Colostmm contains antibodies from the mother s milk that serve to immunize the neonate against disease (37). These antibodies can be absorbed by the neonate only within the first few days of its life there is no placental transfer of antibiotics in mminants (37). 

In agreement with abundant mRNA in mammary gland, high levels of apelin are present in bovine colostrum oral intake of apelin might modulate immune responses in neonates [4]. 

Inflammatory and immune diseases Autoimmune disease (A,I), asthma (A), osteoarthritis (I), rheumatoid arthritis (I), septic shock (A,I), infections (A,I), familial cold auto-inflammatory syndrome (I), Muckle Wells syndrome (I), chronic infantile neurological cutaneous and articular syndrome/neonatal onset multisystemic inflammatory disease (CINCA/NOMID) (I), Crohn s disease (I), gout (I), acute renal failure (A,l)... 

Ueno T, Hara K, Willis MS, et al. Role for CCR7 ligands in the emigration of newly generated T lymphocytes from the neonatal thymus. Immunity 2002 16 205-218. 

In passively immunized neonatal rats, Tyv-specific antibodies exclude larvae from the epithelium (Appleton et al., 1988), where large numbers of excluded larvae become entrapped in mucus (Carlisle et al., 1991a). Similarly, when immune adult rats are challenged with larvae, many luminal parasites are observed entrapped in mucus (Lee and Ogilvie, 1982 Bell et al, 1984). Larvae are neither injured nor killed by mucus entrapment, which is reversible and is not a requirement for expulsion (Carlisle et al., 1990). Rather, mucus appears to participate in expulsion by temporarily confining larvae to the lumen, thus facilitating their elimination from the intestine by normal physiological processes. 

Enterotoxigenic E. coli epitope and rotavirus epitope fused to CTB Potato tuber Mice developed detectable levels of serum and intestinal antibodies. Immunogenic in mice against ETEC, rotavirus, and V. cholerae when delivered orally. Symptoms reduced in passively immunized mouse neonates following rotavirus challenge. 63... 

Transformed cells expressing tumour-specific surface antigens that closely resemble normal surface antigens may not induce an immune response. Furthermore, some tumour antigens, although not usually expressed in adults, were expressed previously during the neonatal period (i.e. just after birth) and are thus believed by the immune cells to be self . 

Administering IVFE over 12 to 24 hours in adults and 20 to 24 hours (0.15 g/kg/hour) in neonates appears to be the best strategy for promoting IVFE clearance and minimizing negative immune function effects. 

Sensitivity of the immune system to Pb appears to differ across life stages, and studies in rodents suggest that the gestational and neonatal periods are the most sensitive. Compared to adults, the increased dose sensitivity of the embryo-fetus would appear to fall in the range of 3-12X depending upon the immune endpoint considered. Recent studies have suggested that exposure of embryos to Pb producing neonatal BLLs below 10 pg/dL can also produce later-life immunotoxicity (Table 12.2). Furthermore,... 

Dynatov, V.A. and Lawrence, D.A., Neonatal lead exposure potentiates sickness behavior induced by Listeria monocytogenes infection of mice, Brain Behav. Immun. 16, 477, 2002. 

A review of the literature on chemical-induced immunosuppression in rats and mice, exposed during the pre- and/or postnatal period, was compared to exposure of adults. Five known immunosuppressants (i.e., TCDD, TBTO, DES, Pb, and diazepam) were reviewed. The data revealed that the developing immune system was more sensitive to chemical exposure than the mature immune system. Based on these evaluations, the authors concluded that it was reasonable to assume that testing only in adults would not provide a sufficient level of sensitivity to define immunotoxicity in the neonate 132. In summary, this chapter provides compelling evidence that the developing, compared to the mature, immune system is more vulnerable to perturbation. 

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