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Brucella vaccine 116 bullous pemphigoid
initial infection. Cell-mediated immune responses confer
protective immunity. Brucella is a facultative, intracellular
bacteria controlled by macrophage activation and granuloma
formation to isolate the infectious agents. Both CD4 +
and CD8 + T lymphocytes participate in the experimental
infection in mice. The CD4 + T cells synthesize interferon-γ
(IFN-γ) and the CD8 + T cells lyse ineffective macrophages.
Interleukin-12 (IL-12) is important in controlling the differentiation
of T cells and natural killer (NK) cells to produce
IFN-γ, which facilitates cell-mediated immunity. IL-1,
TNF-α, IL-6, M-CSF, and G-CSF are all produced during
experimental infection. Minute granulomata comprised of
epithelioid cells, neutrophils, mononuclear leukocytes, and
giant cells are produced in the tissues of humans infected
with Brucella species. Hepatosplenomegaly is a common
clinical feature. Delayed-type hypersensitivity, which is
a correlate of cell-mediated immunity, induces immunopathological
changes. The granulomata is accompanied
by development of a severe, generalized, delayed-type
hypersensitivity response that mimics many features of the
infection. Diagnosis depends on testing for antibodies in
the serum. Most of the antibodies are directed against LPS.
The agglutination test is the one most widely used but is
being replaced by ELISA. Whereas B. abortus strain 19 is
employed to immunize cattle and B. melitensis stain Rev 1
is used to immunize sheep and goats, human vaccination
has been employed essentially only in Russia. Other preventive
measures include pasteurization of milk products.
Brucella vaccine
A preparation used for the prophylactic immunization of
cattle. It contains live, attenuated Brucella abortus microorganisms.
A second vaccine comprised of McEwen strain
45/20 killed microorganisms in a water-in-oil emulsion
(adjuvant) has also been used.
brucellin
A substance similar to tuberculin but derived from a culture
filtrate of Brucella abortus that is used to test for the presence
of delayed-type hypersensitivity to Brucella antigens.
The test is of questionable value in diagnosis.
brush border
Dense microvilli on the apical surfaces of intestinal epithelial
cells that significantly increase their surface area.
brush-border autoantibodies
Antibodies associated with Heymann nephritis in rats as
well as in half of patients with ulcerative proctocolitis, in
20% of patients with antibodies to Yersinia enterocolitica
0:3, and in patients who are extensively burned.
Bruton’s agammaglobulinemia
Synonym for X-linked agammaglobulinemia.
Bruton’s X-linked agammaglobulinemia
One of the more common immunodeficiencies. There is
a failure of B cell precursors, i.e., pro-B cells and pre-B
cells, to mature into B cells. The defect is in rearrangement
of immunoglobulin heavy chain genes. B cell maturation
ceases after the heavy chain genes are rearranged. Light
chains are not produced, which prevents assembly of the
complete immunoglobulin molecule. The block in differentiation
is attributable to mutations in cytoplasmic B cell
tyrosine kinase (Btk). It occurs almost entirely in males and
is apparent after 6 months of age following disappearance
of the passively transferred maternal immunoglobulins.
Patients have recurrent sinopulmonary infections caused
by Haemophilus influenzae, Streptococcus pyogenes,
Staphylococcus aureus, and Streptococcus pneumoniae.
These patients have absent or decreased B cells and
decreased serum levels of all immunoglobulin classes. The
T cell system and cell-mediated immunity appear normal.
BSA
Abbreviation for bovine serum albumin.
BSF (B lymphocyte stimulatory factor)
Refer to interleukins 4, 5, and 6.
B symptoms
Inexplicable rapid weight loss, fatigue, fever, and night
sweats often associated with chest pain that occur in lymphoma
patients.
Btk
A protein tyrosine kinase coded for by the defective gene in
X-linked agammaglobulinemia (XLA). B lymphocytes and
polymorphonuclear neutrophils express the Btk protein. In
patients with XLA (Bruton’s disease), only the B lymphocytes
manifest the defect, and the maturation of B lymphocytes
stops at the pre-B cell stage. Rearrangement of heavy chain
but not light chain genes occurs. The Btk protein may have a
role in linking the pre-B cell receptor to nuclear changes that
result in growth and differentiation of pre-B cells.
bubble boy
A 12-year-old male child maintained in a germ-free (gnotobiotic)
environment in a plastic bubble from birth because
of his severe combined immunodeficiency (SCID). A bone
marrow transplant from a histocompatible sister was treated
with monoclonal antibodies and complement to diminish
alloreactive T lymphocytes. The boy died of a B cell
lymphoma as a consequence of Epstein–Barr virus-induced
polyclonal gammopathy that transformed into monoclonal
proliferation, leading to lymphoma.
Buchner, Hans (1850–1902)
German bacteriologist who was a professor of hygiene in
Munich in 1894 and discovered complement. Through his
studies of normal serum and its bactericidal effects, he
became an advocate of the humoral theory of immunity.
buffy coat
The white cell layer that forms between the red cells and
plasma when anticoagulated blood is centrifuged.
bullous pemphigoid
A blistering skin disease with fluid-filled bullae developing
at flexor surfaces of extremities, groin, axillae, and inferior
abdomen. Immunoglobulin G (IgG) is deposited in a linear