Polyclonal hypergammaglobulinemia polyclonal gammopathy

Pathophysiology of polyclonal gammopathy Polyclonal hypergammaglobulinemia is usually due to an underlying infectious, inflammatory or neoplastic disorder such as a carcinoma. Antigen is processed by antigen-presenting cells which activate T cells to induce proliferation of antigen-specific B cells. Under the influence of cytokines such as interleukin 6 IL-6 , these B cells differentiate into antibody-producing plasma cells. These polyclonal plasma cells increase in number in the bone marrow,...

Principles of immunoelectron microscopy

Immunoelectron microscopy can be defined as any technique that uses antibodies, or molecules that interact with antibodies for example, protein A or protein G , in conjunction with electron microscopy to localize ultrastructurally antigens or antibodies in cells and tissues. In addition, a number of other biological macromolecules whose specific ligand-bind-ing properties are known can be used for example, lectins . Immunoelectron microscopy was a term that was originally confined to studies...

Natural infection and immune response to parvovirus B19

The natural course of parvovirus B19 infection has been evaluated by experimental infection of normal volunteers and in a prospective study of a major epidemic. After intranasal inoculation of normal per sons, the virus infects and replicates in erythroid bone marrow cells. Viremia is first detected by day 6 and can reach peak levels > 1014ml 1 serum. Infection kills the host cells, so that at the peak of infection, almost no erythroid cells except for a few virtually pathognomonic giant...

Antigenic variation in HIV

With the availability of extensive HIV nucleotide sequence data, genetic diversity among AIDS viruses can be compared. The envelope gene of HIV-1 contains five hypervariable regions which are flanked by conserved regions. Sequence diversity is a characteristic of many RNA viruses. They are genetically error-prone by virtue of their DNA-dependent R.NA polymerase, a step in their replication cycle which escapes correction by host cell enzymes ('subediting'). It has been estimated that the HIV-1...

Spontaneous animal models for organspecific autoimmune diseases

Obese strain of chickens as an animal model for Hashimoto's thyroiditis During the first few weeks after hatching, obese strain (OS) chickens develop a hereditary spontaneous autoimmune thyroiditis (SAT) that resembles human Hashimotos disease in all clinical, histopathological, endocrinological and immunological aspects. The thyroid glands of OS chickens become heavily infiltrated by mononuclear cells, finally resulting in complete destruction of their architecture entailing clinical symptoms...

Animal models of Addisons disease

Idiopathic Addisons disease occurs spontaneously in dogs and more rarely in cats. In the few cases that have undergone autopsy, atrophy, regeneration of adrenocortical cells and chronic inflammation of the adrenal cortex have been observed. The cause of adrenal insufficiency in dogs is probably of autoimmune, not tubercular, origin. A preferential occurrence in Chow-Chow dogs suggests a genetic predisposition. Adrenal autoimmunity with lesions of the chronic inflammatory type has been...

False food allergy or pseudoallergy

These types of reaction outnumber the true immunologically mediated ones. Various clinical syndromes are also known to be induced by such reactions, for example chronic urticaria, anaphylactic shock, intermittent diarrhea and irritable bowel syndrome, migraines, rhinitis and asthma. Table 3 lists some of the substances and mechanisms implicated in false food reactions. Table 2 Investigations for the diagnosis of food allergy 1. Skin tests (prick) with, where possible, purified allergens 2....

Routes of antigen administration

There are two general routes of antigen administration - parenteral and mucosal. The former refers to routes which involve penetration of the skin the latter refers to absorption of antigen through a mucosal layer. A number of routes are used in experimental work, including intradermal (i.d.), subcutaneous (s.c.), intramuscular (i.m.), intraperitoneal (i.p.) and intravenous (i.v.) administration. Three routes are mainly used in human administration. The smallpox (vaccinia) vaccine was routinely...

B cell deficiency diseases

The physiological importance of B cell function is revealed by diseases that result from selective B cell deficiencies and consequent lack of antibodies (agammaglobulinemia). Bruton's agammaglobulinemia (XLA) is an X-linked defect in B cell maturation in humans, with arrest at the Pre-B I stage and a resulting deficiency in all immunoglobulin classes. A corresponding B cell maturation defect, the Xid mutation, also occurs in CBA N mice. In male children with XLA, the maturation block results...

Invertebrate Immune Systems

Christopher J Bayne, Department of Zoology, Oregon State University, Corvallis, Oregon, USA Gerardo R Vasta, Center of Marine Biotechnology, Baltimore, Maryland, USA Invertebrates, despite their lack of lymphoid immune systems, recognize and respond to nonself substances at least as efficiently as do vertebrates. Invertebrates rely on a diversity of mechanisms, some of which are inducible however, the responses are in most cases short-lived and do not discriminate between individual pathogens....

The immunological role of calcitriol

The secretory role of macrophages for calcitriol In contrast to endocrine synthesis of calcitriol in the kidney, normal macrophages have also been shown to synthesize calcitriol when activated by agents such as interferon y and lipopolysaccharide. Production of the hormone may thus act as part of the normal immune response and induction of calcitriol synthesis in response to infection may stimulate the synthesis of other inflammatory mediators such as interleukin 1 (IL-1), which will in turn...

Effects of mercury on the immune system

Little is known about the principal mechanism by which mercury affects the immune system. An effect on the selection mechanisms in the thymus has been suggested, allowing potentially autoreactive cells to escape into the periphery. A direct mitogenic action on lymphocytes seems to be well established and could result from the chemical effects of this heavy metal on some cell membrane components, such as calcium channels, or direct action on nuclear proteins. Other possible mechanisms would be...

Basic biology of the rabbit immune system

The rabbit immune system is comparatively similar to the human system with only minor differences in tissue and cellular organization. The rabbit gut-as-sociated lymphoid tissue (GALT) is organized into a prominent appendix, obvious Peyer's patches and some diffuse lymphatic nodules. The human appendix is vestigial and has more diffuse lymphatic nodules. The GALT, as well as other peripheral tissues of the rabbit and human, are innervated with a well-developed lymphatic system of nodes and...

Marsupial Immune System

Richard H Sutton, Department of Veterinary Pathology, University of Queensland, Queensland, Australia The Marsupialia are a widely divergent mammalian order which are phylogenetically distinct from Eutheria. It is an order in which the female has two uteri and two lateral vaginae. The young are born at a very early stage of development and continue their growth while permanently attached to a teat, which is usually enclosed within a pouch or marsupium. Many groups or families of the order have...

Diseases caused by maternal antibodies

Antibodies against blood group antigens can cause hemolytic disease of the newborn. The mild hemolytic disease caused by ABO incompatibility occurs almost exclusively in children of mothers belonging to group O. It is the most common antibody-mediated perinatal disease with an incidence varying from 1 to 5 in different ethnic populations. Though laboratory findings of this disease arc common, only a minority of the children require treatment. Before the discovery that hemolytic disease due to...