Visualization of fluorescent erythrocytes in the microcirculation.

Erythrocytes loaded internally with FITC-BSA can be readily visualized in the microcirculation by using a television camera and a fluorescence microscope. Flow properties of the erythrocytes and their adherence to the vascular endothelium or erythrophagocytic cells can be observed. This procedure should also be useful to delineate the microcirculation under circumstances where infused free FITC-BSA can escape into the interstitial tissue.

Erythrocyte carriers.

The properties of erythrocytes used as carriers for drugs, enzymes, and DNA will be reviewed. One potential application is delivery of these substances to cells responsible for or capable of erythrophagocytosis and are located primarily in the liver and the spleen. A second potential application depends on the ability of loaded cells to survive for substantial periods of time in the circulation after reinfusion. Circulating cells used as drug carriers may be able to modify the pharmacokinetics of administered drugs and if used as enzyme carriers, they may be able to alter the level of various substances in the plasma. Erythrocytes in vitro may fuse with recipient cells, introducing their contents in a functional form into recipient cells. Nucleic acids, either RNA or DNA, as well as enzymes or other entrapped substances, may be transferred in this manner.

Unique V kappa group associated with two mouse L chain genetic markers.

The C.C58 and C.AKR congeneic strains of mice differ from BALB/c at loci on chromosome 6 which govern kappa light chain variable region (V kappa) polymorphisms and the Lyt-2 and Lyt-3 alloantigens. Amino acid sequence analysis of light chains of myelomas induced in these strains revealed one light chain, C.C58 M75, that had an NH2-terminal serine and differed sufficiently from published V kappa sequences to define a new V kappa group, V kappa (Ser), apparently not expressed by BALB/c mice. Peptide map analysis indicated that the M75 light chain contained the IB-peptide marker, a V kappa polymorphism expressed by C.C58 but not BALB/c mice, which is determined by the IgK-Trpa allele present on chromosome 6. This same light chain was found by isoelectric focussing to correspond to IgK-Ef1a, another V kappa genetic marker of C.C58 and C.AKR. Isoelectric focussing of approximately 200 C.C58 and C.AKR myeloma light chains revealed three additional C.C58 and four C.AKR light chains that corresponded to IgK-Ef1a-specific light chains. All three additional C.C58 light chains belonged to the V kappa (Ser) group and contained the IB-peptide marker. Thus, the differences in V kappa repertoires represented by the IB-peptide and IgK-Ef1a markers and controlled by genes on chromosome 6 appear to reflect expression (or failure of expression) of a distinct group of V kappa regions.