Two irritants, phosphate-buffered saline and alcohol, and antigens including killed Brucella abortus, live B. abortus, Staphylococcus aureus, and rat parvovirus were separately infused into rat mammary glands during pregnancy, and by using immunofluorescent techniques, the numbers of immunoglobulin-containing cells in glands during lactation and involution were determined. The study provided ba...

BACKGROUND The pathogenesis of some primary humoral immunodeficiencies, such as transient hypogammaglobulinemia of infancy (THI) and immunoglobulin (Ig) A deficiency, remains unknown and can render diagnosis problematic. OBJECTIVE In the present study, we used flow cytometry to analyze peripheral blood B-cell subsets in patients with THI and unclassified hypogammaglobulinemia (UCH), partial I...

IgA deficiency is the most common primary immunodeficiency in humans. Comparative analysis of gene expression in PBMC from IgA-deficient (IgAd) and normal donors using functional multiplex panels showed overexpression of the Caspase-1 (CASP-1) gene. Cells from all the IgAd donors (n = 7) expressed 4–10-fold caspase-1 mRNA over normal controls (n = 5). CD19+ B cells from all IgAd donors produced...

We successfully cloned antigen-specific T cells from murine gut-associated lymphoreticular tissue, i.e., Peyer's patches, which are dependent upon T cell growth factor and independent of antigen for continuous growth. These clones exhibit helper activity for IgA responses to sheep erythrocytes (SRBC) and have been designated T helper (Th) A. Two broad categories of Th A clones have been maintai...

Switching from IgM to IgG and IgA is essential for antiviral immunity and requires engagement of CD40 on B cells by CD40L on CD4(+) T cells. HIV-1 is thought to impair CD40-dependent production of protective IgG and IgA by inducing progressive loss of CD4(+) T cells. Paradoxically, this humoral immunodeficiency is associated with B cell hyperactivation and increased production of nonprotective ...

The immunoglobulin A (IgA) response is thymic dependent (TD), 1 because athymic, nude mice exhibit depressed serum IgA levels (1-3) and neonatally thymectomized rabbits do not undergo IgA responses (4). Furthermore, human T cell dysfunctions contribute to IgA deficiency in some individuals (5-7). However, it has been difficult to directly study T cell regulation of IgA responses to specific ant...

B cells have the potential to respond to an antigen by producing antibodies with a variety of variable and constant regions. We have quantitatively analyzed B-cell potential at the single cell level to determine the effect of lymphoid tissue site and antigen load on the expression of variable and constant regions. Concerning variable region expression, although the total frequency of B-cell pre...

Mucosal antigens induce generation of lamina propria plasma cells (PCs) that secrete dimeric immunoglobulin A (IgA) destined for transport across the epithelium. In addition, blood contains monomeric IgA. To study the relationship between mucosal and systemic antibody responses, we took advantage of celiac disease patient samples for isolation of gut PCs as well as serum IgA and IgG reactive wi...

Next to conventional B cells (or B-2 cells), peritoneal B-1 cells have been shown to contribute significantly to the production of IgA-secreting plasma cells in the gut. Evidence for this was mainly based on studies comprising manipulated animals, including lethally X-irradiated and transgenic mice. To examine the ability of peritoneal B-1 cells from untreated mice to switch actively to IgA in ...

Normal intestinal mucosa contains abundant immunoglobulin A (IgA)-secreting cells, which are generated from B cells in gut-associated lymphoid tissues (GALT). We show that dendritic cells (DC) from GALT induce T cell-independent expression of IgA and gut-homing receptors on B cells. GALT-DC-derived retinoic acid (RA) alone conferred gut tropism but could not promote IgA secretion. However, RA p...