Monoclonal antibodies to L-asparaginase

Summary Five hybridomas secreting monoclonal antibody toE. coli L-asparaginase were isolated. These monoclonal antibodies were classified into 3 different subclasses; Ig G₁ (1 clone), Ig G₂ (2 clones) and Ig G₃ (2 clones). One of them possessed anti-L-asparaginase neutralizing activity. Four antibodies examined demonstrated a linear Langmuir binding plot and binding affinities, with equilibrium dissociation constant (K_d) ranging between 2.5×10^–9M and 6.3×10^–10 M. The monoclonal antibodies should be useful probes for investigation of the enzyme activity.     

Monoclonal antibodies against antigens on breast cancer cells

Of 360 mAb obtained in a cell fusion experiment with the spleen cells of a mouse immunized with a mixture of different human breast carcinoma cell lines, 30 mAb were selected which reacted more strongly with tumor cells than with (noncancerous) fibroblasts. These mAb were tested for reactivity with additional types of cancerous and noncancerous tissues. Two mAb showed high tumor selectivity, but the corresponding epitopes on individual tumor cells were heterogeneously expressed. The mAb will be evaluated for in vivo applications.     

Monoclonal antibodies against antigens on breast cancer cells

Summary Of 360 mAb obtained in a cell fusion experiment with the spleen cells of a mouse immunized with a mixture of different human breast carcinoma cells lines, 30 mAb were selected which reacted more strongly with tumor cells than with (noncancerous) fibroblasts. Theses mAb were tested for reactivity with additional types of cancerous and noncancerous tissues. Two mAb showed high tumor selectivity, but the corresponding epitopes on individual tumor cells were heterogeneously expressed. The mAb will be evaluated for in vivo applications.     

Monoclonal antibodies against functionally distinct sites on the delta-endotoxin ofBacillus thuringiensis var.thuringiensis

Summary Monoclonal antibodies against the toxic units ofBacillus thuringiensis delta-endotoxin were raised by the hybridoma technique and detected by an indirect enzyme-linked immunosorbent assay (ELISA). Out of 5 positive clones, I was found to secrete antibodies which inactivate the toxin.     

On the distribution of plasma L-asparaginase

Summary The guinea-pig,Cavia porcellus, is unusual in possessing plasma L-asparaginase, an enzyme with anti-tumor activity. 21 additional species have been examined as to the presence of this enzyme: the results confirm and extend its remarkably limited species distribution.This work was supported in part by grant GM/CA 25378 from the National Institute of General Medical Sciences, National Institutes of Health.We are grateful to dr Hanna Hensch, Philadelphia Zoological Garden, and Ms Joan Whitla and Dr Richard J. Montali, National Zoological Park/Smithsonian Institution, for samples of frozen serum.To whom correspondence should be addressed.     

On the distribution of plasma L-asparaginase

The guinea-pig, Cavia porcellus, is unusual in possessing plasma L-asparaginase, an enzyme with anti-tumor activity, 21 additional species have been examined as to the presence of this enzyme: the results confirm and extend its remarkably limited species distribution.     

Crystallization and properties of L-asparaginase fromEscherichia coli

Zusammenfassung L-Asparaginase ausE. coli ist bei hoher Proteinkonzentration zwischen pH 5,0 und 6,5 und geringer Ionenstärke durch Zugabe von Äthanol in der Kälte leicht kristallisierbar. Bei pH 5,0 und pH 6,5 entstehen unterschiedliche Kristallformen. Das durch Kristallisation gereinigte Enzym lässt sich bei erhöhter Temperatur inaktivieren, wobei das Produkt der Inaktivierung ebenso kristallisiert werden kann. Es zeigt das gleiche Verhalten in der Ultrazentrifuge wie das aktive Enzym.     

Cross-reactive monoclonal antibodies to alcohol dehydrogenases

Three anti-horse liver alcohol dehydrogenase (HLADH) monoclonal antibodies are described. Two are specific for ADH and cross-react with class I and II enzymes from mouse, horse and Chinese hamster. They are specific for the native enzyme but do not inhibit enzyme activity except when combined at high concentration. The third antibody was isolated as a response to rabbit metallothionein. It binds metalloproteins and inhibits ADH activity.     

Cross-reactive monoclonal antibodies to alcohol dehydrogenases

Summary Three anti-horse liver alcohol dehydrogenase (HLADH) monoclonal antibodies are described. Two are specific for ADH and cross-react with class I and II enzymes from mouse, horse and Chinese hamster. They are specific for the native enzyme but do not inhibit enzyme activity except when combined at high concentration. The third antibody was isolated as a response to rabbit metallothionein. It binds metalloproteins and inhibits ADH activity.     

An attempt to produce antibodies to oxytocin and vasopressin

Zusammenfassung Mit einem Oxytocin-Albumin-Konjugat bzw. mit einem Lysin-Vasopressin-Albumin-Konjugat konnten bei Kaninchen spezifische Antikörper hervorgerufen werden. Die gegen Oxytocin-Albumin-Konjugat gerichteten Antikörper scheinen auch einen gewissen inaktivierenden Effekt auf genuines Oxytocin zu haben.     

Vitamin A antibodies: Application to radioimmunoassay

Summary A radioimmunoassay for serum vitamin A is described which can detect as little as 1 ng of retinol. The statistical characteristics of this assay are presented and its use in a nutritional experiment is discussed.This work was supported by United States Public Health Service grant 2 RO1 AM19716.     

Polyreactive antibodies in adaptive immune responses to viruses

B cells express immunoglobulins on their surface where they serve as antigen receptors. When secreted as antibodies, the same molecules are key elements of the humoral immune response against pathogens such as viruses. Although most antibodies are restricted to binding a specific antigen, some are polyreactive and have the ability to bind to several different ligands, usually with low affinity. Highly polyreactive antibodies are removed from the repertoire during B-cell development by physiologic tolerance mechanisms including deletion and receptor editing. However, a low level of antibody polyreactivity is tolerated and can confer additional binding properties to pathogen-specific antibodies. For example, high-affinity human antibodies to HIV are frequently polyreactive. Here we review the evidence suggesting that in the case of some pathogens like HIV, polyreactivity may confer a selective advantage to pathogen-specific antibodies.     

Fluorescent studies of antibodies to rabbit male urogenital tissue

Zusammenfassung Immunofluoreszenzoptische Vorversuche mit Seren männlicher Kaninchen, deren KoagulationsdrÜsen Schädigung durch wiederholtes Tieffrieren in situ ausgesetzt waren, lassen vermuten, dass diese Sera Antikörper enthalten, die mit dem Zytoplasma von Azinusepithelzellen und anderen Anteilen der KoagulationsdrÜsen reagieren.     

Enzyme-linked immunosorbent assay to detect anti-sea nettle venom antibodies

Summary A micro enzyme-linked immunosorbent assay has been developed to detect serum antibodies to sea nettle venom. This sensitive assay is useful for monitoring specific immunological response in envenomated patients or in immunized animals.These experiments were funded in part by grant ES01474 from the National Institutes of Health and the Brandywine Foundation. The authors wish to acknowledge the technical aid and assistance of Helene Rubinstein and Robert Miller.