Epitope specificity of hemagglutinating monoclonal anti-B antibodies]

Fine epitope specificity of ten monoclonal antibodies (MA) agglutinating red blood cells B was studied. Three methods were used: 1) inhibition of MA binding to natural antigen by synthetic oligosaccharides (OS) and their polyacrylamide conjugates, 2) direct MA binding to a series of synthetic OS-polyacrylamide conjugates differing in carbohydrate epitope density, 3) direct MA binding to the affinity sorbents. It is shown that all antibodies studied prefer trisaccharide B determinant Gal alpha 1-3(Fuc alpha 1-2) Gal independently of their ability to discriminate serological subgroups of B erythrocytes (B, Bweak, B3). The correlation of the MAs epitope specificity with their ability to agglutinate red blood cells B subgroups is discussed. Of an interest is that MAs which are able to agglutinate any B subgroups also bing the synthetic tetrasaccharide Gal alpha 1-3(Fuc alpha 1-2)Gal beta 1-3GalNAc, a B type 3 determinant.     

Differential expression of keratin 19 in normal human epithelial tissues revealed by monospecific monoclonal antibodies

Summary Three monospecific monoclonal antibodies (BA16, BA17 and A53—B/A2) recognizing different epitopes of the human keratin 19 were used to determine tissue distribution of this 40 kDa keratin polypeptide. Immunohistochemical methods revealed four different staining patterns among normal human epithelial tissues: firstly, complete negativity of the epidermis, sebaceous glands, hepatocytes and other tissues; secondly, homogeneous positivity as seen for example in the gall bladder and urinary bladder epithelium, endometrium and many other epithelia; thirdly, a mosaic of positive and negative cells among mammary gland luminal cells, prostate epithelia and some other epithelia and fourthly, a more complex heterogeneous pattern found in non-keratinizing squamous epithelia and hair follicles with generally the basal layer being the most strongly or sometimes exclusively stained. The pattern seen in non-keratinizing squamous epithelia varied considerably according to the fixation method and the antibody used as well as among different donors and in different areas of the same organ. The other three staining patterns were on the other hand nearly identical with all three antibodies on both frozen sections and sections of methacarn-fixed paraffinembedded tissues. Our results provide evidence for differential expression of the human keratin 19 at the single cell level, an observation which could be exploited in the study of epithelial differentiation and pathology.     

An immunocytochemical study of normal and abnormal human cerebrospinal fluid with monoclonal antibodies to glial fibrillary acidic protein

The presence of astrocytes in the cerebrospinal fluid (CSF) of patients may be of diagnostic importance. However, the frequency with which astrocytes are shed into normal and abnormal human CSF is unknown. This issue was studied using monoclonal antibodies to an astrocyte-specific antigen, glial fibrillary acidic protein (GFAP), and immunoperoxidase cytochemistry. The study was prospectively conducted on 108 CSF preparations diagnosed as normal, reactive, metastatic malignancy or suspicious for metastatic malignancy. To validate these methods, cells from a clonal human glioma cell line, which contains astrocytes rich in GFAP, were processed in a manner identical to that used for the CSFs obtained from patients. Studies of the human glioma cell line demonstrated intense GFAP immunoreactivity in the majority of the malignant astrocytes. In contrast, none of the CSFs contained GFAP-positive cells. We conclude that immunocytochemical methods can detect GFAP in neoplastic human astrocytes but that nonneoplastic GFAP-positive cells are uncommon in human CSF; such cells were not seen in our large series of normal and abnormal human CSFs. The immunocytochemical detection of GFAP may be a useful criterion for distinguishing malignant astrocytes from other types of malignant cells in human CSF.     

Characterization of monoclonal antibodies against human parvovirus B19

Eleven hybridoma cell lines producing mouse monoclonal antibodies (mAbs) against human parvovirus B19 were established. Their specificity was as follows. Approximately 5% of fetal erythroid cells inoculated with B19 reacted with all the mAbs and with anti-B19 positive human serum, but not with negative serum by indirect double immunofluorescence staining. All the mAbs recognized both VP-1 (84 kDa) and VP-2 (58 kDa) capsid proteins of B19 virions propagated in vitro and in vivo by Western blotting, and immunoprecipitated B19 virions.     

Extremely potent human monoclonal antibodies from COVID-19 convalescent patients

1. Download : Download high-res image (174KB)
2. Download : Download full-size image

     

Pericapillary spongy sheaths in the human spleen. An immunohistological study

Antisera to extracts of human hyaline cartilage allow distinct visualization of extracellular structures of adventitial sheaths around arterial capillaries in the red pulp and marginal zone in the human spleen. These pericapillary sheaths have a prominently spongy character indicating their essential filter function. In childhood they are most marked. In premature and stillborn infants they sometimes occupy whole stretches of pulp cords, whereas in old age they are frequently diminished to small formations lacking a distinctly spongy structure.