Immune system table

Hypersensitivity (hypersensitivity reaction) refers to undesirable reactions produced by the normal immune system (Table 15.5). Hypersensitivity reactions require a pre-sensitised (immune) state of the host. Exposure may be by ingestion, inhalation, injection or direct contact. 

There is also a well-established biochemical and clinical relationship between malnutrition and immune function. Alterations in the immune system (Table 136-2) represent an end-organ or functional response to malnutrition and may reflect a decline in lean body mass as well as a deficiency in specific nutrients such as zinc. Clinically, this is manifested as an increased incidence of infection. 

Immunoglobulin Molecules - There are five classes of immunoglobulin molecules, which carry out various functions in the immune system (Table 7.3). All are built from the same basic immunoglobulin pattern (Figure 7.32). Different kinds of antibodies may contain from one to five immunoglobulin molecules. When more than one is present, the monomers are linked by a second type of polypeptide, called a J chain (see Table 7.3). 

The central aspect of clinical testing in infants should include the evaluation of a diverse spectrum of immune functions in response to an added substance. To develop the appropriate tests for assessing the safety of the immunological responses to new substances, it is useful to first identify the target tissues affected by the interaction of ingested substances with the host immune system (Table 6-7). 

The toxicity of 2,4-pentanedione is shown in Tables 3 and 11 to be similar to mesityl oxide, and greater than most other 1,2- or 1,4-diketones or monoketones. Inhalation of low levels of 2,4-pentanedione can cause nausea, eye contact can induce stinging, and recurrent exposure to high concentrations (300—400 ppm) can adversely affect the central nervous system and immune system (325). 

Table II. Serologic Specificity of [ I]Palytoxin-anti-Palytoxin Immune System...

Vaccination of lambs with a contortin-enriched preparation gave a mean reduction in worm burdens of 78% (Table 13.1) (Munn et al., 1987). This result was particularly significant because it showed that proteins expressed on the surface of the gut, albeit from a blood-feeding nematode, could induce high levels of protective immunity when used as an immunogen. These proteins are not normally accessible to the host immune system during the course of infection they are termed hidden or concealed antigens and the immunity conferred by them is described as artificial immunity. 

Table 9.5 The major cellular sources of human TNF-p. As is evident, TNF-a synthesis is not restricted to cells of the immune system, but is undertaken by a wide variety of different cells in different anatomical locations, including the brain...

Nonspecific immunostimulants (Table 9.5) can have widespread effects on the immune system similar to microbially-derived agents, including side effects akin to infection... 

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,... 

As with the development of other organ systems, the development of the immune system is a highly regulated process. Table 19.1 and Figure 19.1 provide a list of known events or markers that occur during immune system development. In humans, hematopoiesis begins at approximately 3-4 weeks of gestation with the development of blood... 

It must be emphasized at the onset that there are still no validated or widely accepted methods for evaluating the effects of a chemical on the developing immune system. This section will consider some of the most appropriate approaches to identifying developmental immunotoxicants, in the context of recommendations and conclusions from many of the activities highlighted in Table 20.1. 

Lymphocytes, the effector cells of the acquired immune system, include morphologically indistinguishable T and B cells, the former divided into CD4+ T helper cells and CD8+ cytotoxic T cells. Since the functions of those cell subsets differ so drastically, it became important to develop tools to distinguish them from each other. Efforts to identify cell subsets according to their expression of different surface antigens have been successful, including various Cluster of Determination (CD) markers (Table 23.1). In addition, cross-reactive monoclonal antibodies, and subsequently developed species-specific polyclonal and monoclonal antibodies towards the major histocompatibility complex (MHC) have been used to label cells in circulation and in tissue sections (Table 23.1). 

Overall, a battery of reagents and assays has been developed that enable the assessment of several aspects of the immune system of marine mammals. These are summarized in Table 23.3. 

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