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: 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: 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.

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 diagnosis.

Abstract: Antigenic epitopes associated with the extracellular segment of the domain which anchors immunoglobulins to the B cell membrane are disclosed. For IgA, the epitopes are present on IgA-bearing B cells but not the secreted, soluble form of IgA. The epitopes can be exploited for therapy and prophylaxis. For example, antibodies specific for the epitopes associated with the anchor and peptide encompassing the epitope domain of IgA can be used to increase secretory IgA production for the purposes of treating patients with infectious diseases and IgE-mediated allergic diseases.

Abstract: Antigenic epitopes associated with the extracellular segment of the domain which anchors immunoglobulins to the B cell membrane are disclosed. For IgA, the epitopes are present on IgA-bearing B cells but not the secreted, soluble form of IgA. The epitope can be exploited for therapy and prophylacsis. For example, antibodies specific for the epitopes associated with the anchor and peptide encompassing the epitope domain of IgA can be used to increase secretory IgA production for the purposes of treating patients susceptible with infectious diseases and IgE-mediated allergic diseases.