Michael Longenecker

The Potential of Synthetic Tumor-Associated Glycoconjugates (S-TAGs) for Generating Monoclonal Antibodies for Breast Cancer Imaging and for Specific Immunotherapy

The Thomsen Friedenreich (TF) antigen may be important for the detection and immunotherapy of a number of common cancers including breast cancer. Revealed on normal human erythrocytes by neuraminidase treatment, TF has been characterized as: β-D-Gal-(1–3)- α-GalNAc, attached to glycophorin or other glycoproteins through O-serine or O-threonine linkages (1). Tn, the TF precursor, is reported to be α-GalNAc-O-serine/ threonine. While TF is normally cryptic due to the presence of a terminal sialic acid residue, Tn is exposed in individuals with a recessive genetic disorder (2). Springer (1) has claimed expression of TF and Tn antigens on over 90% of cancers of the breast, lung and pancreas, although the nature of the molecules which bear these antigens and their exact structures has not been defined.

Ontogeny of Hemopoietic Colony-Forming Units in the Chick Embryo Spleen

Inoculation of spleen cells of chicken embryos onto the chorioallantoic membrane (CAM) of other chicken embryos led to the formation of white (granulocytic) and pink (mixed erythrocytic and granulocytic) hemopoietic colonies. The number of CAM colonies formed was a linear function of the number of cells inoculated indicating that each colony originated from a single colony-forming unit (CAM-CFU). CAM-CFU’s consist of an aggregate of primitive undifferentiated cells which penetrate the ectodermal layer of the CAM, then proliferate and differentiate into mature granulocytes or erythrocytes. Deaggregated CAM-CFU’s failed to form colonies indicating that cell interaction may be required for colony formation. The genetic constitution of the host embryo has no effect on colony formation but mixtures of donor cells from inbred embryo spleen were found to be more efficient colony formers than mixtures of donor cells from non-inbred embryo spleens. Ontogeny studies demonstrated that the chick embryo spleen contains peak hemopoietic activity between fifteen and seventeen days of incubation declining thereafter to undetectable levels two days post hatching. At this time the inoculation of spleen cell suspensions leads to the formation of lymphoid colonies which increase in number with age of the donor.