Abstract: Chimeric antibodies which bind to unique antigenic epitopes of IgE (designated ige.b1) which are present on IgE-bearing B lymphocytes but not basophils are described.

Abstract: Methods of producing monoclonal antibodies that bind to unique antigenic epitopes of IgE (designated ige.bl) which are present on IgE-bearing B cells but not basophils are described. The monoclonal antibodies block binding of IgE to mast cells and basophils in vitro.

Abstract: Anti-idiotypic monoclonal antibodies that recognize the paratope of monoclonal antibodies specific for unique antigenic epitopes of IgE (designated ige.bl) which are present on membrane-bound IgE-expressed by bearing B cells but not on IgE bound to Fc.epsilon.R on basophils are described.

Abstract: The invention relates to antibodies which immunologically bind epitopes present on B cell-bound but not secreted IgA. This is accomplished by targeting extracellular epitopes on the membrane anchoring peptide of the .alpha. chain which form, entirely or in part, antigenic epitopes unique to membrane-bound but not secreted IgA.

Abstract: Antigenic epitopes associated with the extracellular segment of the domain which anchors immunoglobulins to the B cell membrane are disclosed. For IgE, the epitopes are present on IgE-bearing B cells but not basophils or the secreted, soluble form of IgE. Three different isoforms of the C-terminal segment of the human .epsilon. chain resulting from alternative mRNA splicings in the membrane exon region are disclosed, one of which is secreted and not membrane-bound.

Abstract: Disclosed are immunofluorescence staining methods which increase the likelihood that antibodies expressed by a single B cell selected and sorted by fluorescence activated cell sorting are specific for the antigen of interest, and which also allow selection of B cells expressing antibodies of high affinity for the antigen of interest. The selection for B cells expressing antibodies to specific antigens is increased by labeling B cells with at least two antigen probes, where each antigen probe includes the antigen of interest and is labeled with a different fluorochrome. The positive selection is preferably combined with a negative selection step, in which autofluorescent cells and sticky cells are excluded out. The specificity of sorting of the desired B cells can be further enhanced by staining those antigen-specific B cells which produce the immunoglobulin isotype (typically IgG), with targeting molecules reactive with a B cell marker, such as .gamma.

Abstract: The invention relates to a method of stimulating IgA production through administering a peptide which has the sequence of epitopes which are present on B cell-bound but not secreted IgA. This induces production of the antibody itself. These extracellular peptide segments form, entirely or in part, antigenic epitopes unique to membrane-bound but not secreted IgA.

Abstract: Membrane anchoring peptides are attached to the C terminal end of the heavy chain of the various immunoglobulin isotypes (IgM, IgD, IgA, IgE, or IgG). The membrane anchoring peptides span the cell membrane lipid bilayer of B cells thereby affixing the associated immunoglobulin to the cell membrane surface. The extracellular segments of these peptides are unique for different isotypes. Epitopes unique to the B cells which produce each isotype are formed, in whole or in part, by these extracellular segments. These membrane-bound immunoglobulin isotype-specific ("migis") extracellular epitopes are not present on the secreted, soluble form of the immunoglobulins, which are not bound to the cell surface by the membrane anchoring peptides. The antibodies of the invention (and other related products) specifically bind to the extracellular migis epitopes of human .mu. chain, human .delta. chain, or human .gamma. chain.

Abstract: Antigenic epitopes associated with the extracellular segment of the domain which anchors immunoglobulins to the B cell membrane are disclosed. For IgE, the epitopes are present on IgE-bearing B cells but not basophils or the secreted, soluble form of IgE. The epitope can be exploited for therapy and diagnosis. For example, antibodies or immunotoxins specific for the epitopes associated with the anchor domain of IgE can be used to selectively destroy IgE-bearing lymphocytes, thus blocking IgE-mediated allergic reactions.

Abstract: Membrane anchoring peptides which are part of the heavy chain of an associated immunoglobulin (IgM, IgD, IgA, IgE, or IgG), span the cell membrane lipid bilayer of B cells thereby affixing the associated immunoglobulin to the cell membrane surface. The extracellular segments of these peptides are unique for different isotypes, but tend to be very similar among different subclasses of a particular isotype. The extracellular segments form in whole or in part an epitope unique to the B cells which produce each isotype. These membrane-bound immunoglobulin isotype-specific ("migis") extracellular epitopes are not present on the secreted, soluble form of the immunoglobulins, which are not bound to the cell surface by the membrane anchoring peptides. The antibodies of the invention (and other related products) bind the extracellular migis epitopes.

Abstract: The invention includes human .epsilon. chain transmembrane anchor peptide resulting from mRNA splicing other than the C.epsilon.4 exon, the .epsilon.m1 exon, and the .epsilon.m2 exon. Two new peptides in particular have been specifically identified. These novel peptides are not present in the conventional secreted (and circulating) IgE. These peptides provide antigenic sites for antibody binding. Thus, the invention further includes antibodies to such peptide segments, as well as such antibodies conjugated to cytotoxic agents, and their use in extracorporeal or in vivo therapy.

Abstract: Disclosed are monoclonal antibodies and related products which bind to the second variable region of HIV-1 gp120 and synthetic peptides and anti-idiotypic antibodies which induce endogenous production of antibodies with these same properties.

Abstract: Antigenic epitopes associated with the extracellular segment of the domain which anchors immunoglobulins to the B cell membrane are disclosed. For IgE, the epitopes are present on IgE-bearing B cells but not basophils or the secreted, soluble form of IgE. The epitope can be exploited for therapy and diagnosis. For example, antibodies or immunotoxins specific for the epitopes associated with the anchor domain of IgE can be used to selectively destroy IgE-bearing lymphocytes, thus blocking IgE-mediated allergic reactions.

Abstract: Disclosed are immunofluorescence staining methods which increase the likelihood that antibodies expressed by a single B cell selected and sorted by fluorescence activated cell sorting are specific for the antigen of interest, and which also allow selection of B cells expressing antibodies of high affinity for the antigen of interest. The antigen-specific single B cells are to be used in a procedure which amplifies and selects their V.sub.H and V.sub.L sequences. The selection for B cells expressing antibodies to specific antigens is increased by labeling B cells with at least two antigen probes, where each antigen probe includes the antigen of interest and the difference between the two probes is that each is labeled with a different fluorochrome. The positive selection achieved using antigen probes with two different colors is preferably combined with a negative selection step, in which autofluorescent cells and sticky cells exhibiting fluorescence for the third irrelevant surface marker are excluded out.

Abstract: Antigenic epitopes associated with the extracellular segment of the domain which anchors immunoglobulins to the B cell membrane are disclosed. For IgE, the epitopes are present on IgE-bearing B cells but not basophils or the secreted, soluble form of IgE. The epitope can be exploited for therapy and diagnosis. For example, antibodies or immunotoxins specific for the epitopes associated with the anchor domain of IgE can be used to selectively destroy or downregulate IgE-bearing lymphocytes, thus blocking IgE-mediated allergic reactions. Three different isoforms of the C-terminal segment of the human .epsilon. chain resulting from alternative mRNA splicings in the membrane exon region are disclosed, one of which is secreted and not membrane-bound.

Abstract: A method for producing antibodies specific for antigenic associated with the extracellular segment of the domain which anchors immunoglobulins to the B cell membrane is disclosed. The epitopes recognized by the antibodies of the invention are present on IgE-bearing B cells but not basophils or in the secreted, soluble form of IgE.

Abstract: The monoclonal antibodies (mAbs) of the invention bind to a neutralizing epitope on the gp120 glycoprotein of HIV-1. The binding seems to be conformation-dependent, in the sense that altering the conformation of gp120 (by deglycosylating the gp120, by reducing the cysteine bonds in the peptide backbone) will inhibit the binding. The mAbs of the invention are group specific and can neutralize different strains and different isolates of HIV-1. The binding of these mAbs to gp120 is enhanced by the binding of other antibodies to the principal neutralizing determinant (amino acid residue numbers 296-331) of gp120.

Abstract: Antigenic epitopes associated with the extracellular segment of the domain which anchors immunoglobulins to the B cell membrane are disclosed. For IgE, the epitopes are present on IgE-bearing B cells but not basophils or the secreted, soluble form of IgE. DNA constructs encoding chimeric antibodies, with murine variable regions and human constant regions, which bind to this epitope, can be produced and expressed in transfected mycloma cells.

Abstract: Disclosed are immunofluorescence staining methods which increase the likelihood that antibodies expressed by a single B cell selected and sorted by fluorescence activated cell sorting are specific for the antigen of interest, and which also allow selection of B cells expressing antibodies of high affinity for the antigen of interest. The selection for B cells expressing antibodies to specific antigens is increased by labeling B cells with at least two antigen probes, where each antigen probe includes the antigen of interest and the difference between the two probes is that each is labeled with a different fluorochrome. The specificity of sorting of the desired B cells can be further enhanced by staining those antigen-specific B cells which produce the immunoglobulin isotype (typically IgG), with targeting molecules reactive with B cell markers, such as .gamma. chain and CD19, that are conjugated with different fluorochromes.

Abstract: Molecular conjugates which facilitate the attachment of macromolecular drugs onto cellular surfaces and their entry into cells are described. The molecular conjugates comprise a macromolecular drug linked to an "inactivated" membrane blending agent which inserts into the cellular plasma membrane. The membrane blending agent is inactivated by cleavable linkage to a blocking agent which, until released from the conjugate under appropriate conditions, blocks and ability of the membrane blending agent to insert into the cellular membrane. Upon release of the blocking agent, the membrane blending agent is "activated" and the conjugate can be inserted into a cellular plasma membrane. The membrane blending agents can be peptides such as fusogenic or ion channel forming peptides or long chain fatty acids. The blocking agents can be bulky or charged moieties which mask and prevent insertion of the membrane blending agent.