Monoclonal Anti-A and Anti-B on Groupamatic

Abstract. Monoclonal anti-A and Anti-B from mouse-mouse hybrid-myeloma cell lines were tested in automated grouping on Groupamatic 360 C. Both sera were found to be suitable for Groupamatic typing. The anti-B reagent was particularly potent, and could be used in a high dilution.     

Heterogeneity of Anti-A and Anti-B Monoclonal Reagents

Eight anti-A and seven anti-B monoclonal reagents were tested in parallel, with normal and weak ABH red cell phenotypes. A whole range of different reactivity patterns was found, but by making a comparison with the results obtained using polyclonal standard reagents, two major categories of reagents were distinguished: (a) stronger and more specific reagents, and (b) reagents similar to, or weaker than, the standard polyclonal controls. The analysis of the specificity of the reagents by tissue fluorescence staining and reactivity with synthetic oligosaccharides and purified glycolipids confirmed the existence of broad and restricted specificities. Two kinds of anti-A1 reagents are described. One related to type 3/4 structures, which stains the Golgi apparatus, and another with broad anti-A specificity which cross-reacts with 'A-like' structures. The inhibition of anti-A reagents with salivas and synthetic oligosaccharide antigens gave parallel results for the secretor salivas and the difucosylated A antigens.     

Characteristics of Anti-A and Anti-B in Black Zimbabweans

Sera from young, black, group 0 Zimbabwean blood donors were screened for anti-A and anti-B haemolysins. Nearly one fifth of the sera were found to be strongly haemolytic for either A or B cells or both. Some of the sera were titrated for agglutination in saline before and after treatment with dithiothreitol. Serum dilutions beyond the endpoint of agglutination were further tested by the indirect antiglobulin technique using specific anti-IgM and anti-IgG sera. More than 60% of the strongly lytic sera had high titres of IgG (≥ 64). The IgM and IgG concentrations both of anti-A and anti-B were correlated and these levels were in turn correlated with haemolytic activity.     

Universality of Anti-A and Anti-B Human Isolysins1

A simple, sensitive agar-well Lest for the detection and quantification of hemolysis is described and applied to a survey of anti-A and Anti-B isolysins in hitman sera. The isolysins were present in all the sera in which they should be expected according to 1, andsteiner's rule, thus indicating, with a high degree of confidence, that both anti-A and anti-B isolysins are as universal in healthy human adults as the corresponding isoagglutinins.     

Mouse Monoclonal Antibodies with Anti-A, Anti-B and Anti-A,B Specificities; Some Superior to Human Polyclonal ABO Reagents

A series of fusions using mouse myeloma cells and spleen cells from mice immunized with blood group substances or human red cells was performed with the aim of obtaining ABO antibodies suitable for routine blood grouping. Seven strongly agglutinating antibodies against antigens in the ABO system were obtained from 18 fusions. These antibodies were tested extensively in manual and automated routines, and six of them were found to be as good as or better than commercial polyclonal test sera of human origin.     

Salivary Anti-A and Anti-B Activity of Group O Males

Abstract. Anti-A whole saliva agglutinins were detected in 98% and anti-B in 96% of 80 group O males. After subcutaneous injection of 5 group O males with A and B blood group substances, both whole saliva and parotid saliva agglutinins increased in titer. This agglutinating activity was demonstrated to be primarily due to secretory IgA, both pre- and postimmunization. IgG coating activity was also demonstrated in postimmunization whole saliva. In other studies, whole saliva agglutinin titers correlated poorly with saline agglutinin, neutralization-resistant antibody, or hemolysin titers of the corresponding sera. These findings indicate little or no value for whole saliva agglutinins in predicting the nature of serum antibody and support the concept that the secretory immunoglobulin system is distinct from the system producing circulating antibody.     

Fluctuation of Natural Anti-A and Anti-B in High-Titre Ugandans

Abstract. Observation of the fluctuation of high-titre anti-A and anti-B in Ugandan blood donors are reported. Anti-A in group B donors is mostly affected while anti-B in group A and anti-A and anti-B in group O are less affected. The fluctuations appear not to depend on seasons.     

Improved Removal of Anti-A and Anti-B Antibodies from Plasma Using Blood-Group-Active Haptens

Highly efficient anti-blood group A and B immunoadsorbents for extracorporeal treatment were developed by immobilizing A and B trisaccharide and A tetrasaccharide haptens on Sepharose 4FF and Fractogel TSK using three different methods. The adsorption of the IgG and IgM anti-A antibodies was essentially the same regardless of the A hapten used or the method of oligosaccharide coupling. The adsorption of IgM anti-A was found to be more sensitive than IgG anti-A to changes in column flow rate. The binding of both the IgM and IgG antibodies was slightly lower at 37°C than at 22°C. An anti-A/anti-B adsorbent column potentially suitable for treatment of patients was prepared. A column switching system resulted in a more efficient adsorption of antibodies. Hapten leakage from the column was very low. No nonspecific adsorption of plasma proteins to the column (other than traces of albumin) could be detected.     

The Incidence of Anti-A and Anti-B Isoagglutinins in Cord Blood and Maternal Saliva

The distribution of anti-A and anti-B isoagglutinins varies in individuals of different ABO groups in two distinct ways. Individuals of group O differ from those of group A in that anti-B agglutinins are found more commonly in saliva and in milk. This is probably due to differences in the local synthesis of IgA anti-B in the appropriate glands. Mothers of group O also differ from those of groups A and B in transmitting larger amounts of IgG anti-A and anti-B to the circulation of their foetus. This is probably explained by the fact that individuals of group O tend to produce more 7S isoagglutinin than those of groups A and B.     

High Frequency of Anti-A and Anti-B Haemolysins in Certain Ethnic Groups of Nigeria

Out of 11,480 blood donors, 5,380 (46.9%) belonging to a blood group O were screened for the presence of anti-A and anti-B haemolysins. Strong haemolysins (complete lysis of A and/or B cells) were detected in 1,739 (32.3%) of these blood donors. A striking observation was the high frequency of these haemolysins amongst ethnic groups originating from the southern part of Nigeria. Possible causes and consequences during blood transfusion and pregnancy are discussed.     

IgG Subclasses of Anti-A and Anti-B Antibodies Bound to the Cord Red Cells in ABO Incompatible Pregnancies

IgG subclasses were determined in 138 A or B infants weighing over 2,500g, born to O mothers. Direct antiglobulin test (DAT) was positive in 43 infants and negative in 95 with anti-A and/or anti-B antibodies detected by heat elution test. In 59 out of 131 infants without ABO hemolytic disease (ABO-HDN), no IgG subclass was detectable. In the 72 others, IgG1 was found in 29/72, IgG2 in 63/72, and IgG3 was not detected. In 7 infants with ABO-HDN, DAT was positive in 4 and negative in 3. In conclusion, in DAT-positive infants without HDN, IgG1 or IgG2 may be bound to erythrocytes, but the amount of IgG1 is too small to cause hemolysis. In DAT-positive ABO-HDN the amount of IgG1 is sufficient to cause hemolysis. In DAT-negative ABO-HDN, IgG3 is responsible for hemolysis, even though undetectable by DAT.     

The Stimulation of Immune Antibodies Anti-A and Anti-B in Patients after Treatment with Cryoprecipitate and Factor IX Concentrate (P.P.S.B. According to Soulier)

Abstract. Investigations of the sera from group O and A patients with haemophilia-A and -B, and with von Willebrand's disease, revealed that immune antibodies anti-A and anti-B can be stimulated alter treatment with cryoprecipitate and factor IX concentrate (PPSB). The group O sera were investigated only for immune anti-A. The immune properties demonstrated in the sera consisted in an increase in the titre of saline agglutinins and the appearance or increase of incomplete and haemolytic antibodies anti-A or anti-B. The stimulation of immune antibodies anti-A and anti-B is most probably caused by the presence of soluble A and B blood group substances in the products, as A substance could be demonstrated in samples of cryoprecipitate and PPSB.     

The Reactions of IgG and IgM Anti-A and Anti-B Blood Group Antibodies with 125I-Labelled Blood Group Glycoproteins

Abstract. The reactions between IgG and IgM anti-A and anti-B and ¹²⁵I-labelled A and B blood group glycoproteins were investigated by a modification of the Farr technique. Inhibition curves obtained in a radioimmunoassay system indicate that IgM anti-A and anti-B antibodies have a significantly higher binding constant for A and B glycoproteins than IgG anti-A and anti-B. The observed difference in binding constant may explain the fact that A and B glycoproteins readily inhibit agglutination of A and B red cells by IgM anti-A and anti-B but less readily inhibit agglutination by IgG anti-A and anti-B.     

Comparison of IgM and IgG Anti-A and Anti-B Levels in Asian, Caucasian and Negro Donors in the North West Thames Region

This study was undertaken to test the widely held belief that higher levels of immune anti-A and anti-B are characteristic of Negro and Asian populations with a corresponding increased risk factor for AB0 haemolytic disease of the newborn. Overall, 300 serum samples from male and female Asian. Caucasian and Negro blood donors in the North West Thames Region of groups A, B and 0 were collected. The sera were titrated in microplates against pooled group A1 and pooled group B red blood cells. Although the results show that the highest levels for IgG anti-A and anti-B were found in group 0 female Negro donors, statistically these levels are not significantly higher than those of the other group 0 donors tested. We suggest that the potent anti-A and anti-B reported by others in Negro and Asian populations may arise from environmental rather than genetic factors.     

Allo-Antigens and Allo-Antibodies of the Ko System, Serological and Genetic Study

Abstract. Four new cases of anti-Ko^a allo-antibodies and a third case of anti-Ko^b antibody are described. These IgM thromboagglutinating antibodies present a maximum reactivity at 37 °C and at pH 7. The cross-reaction of anti-Ko^b antibody with antigen Ko^a is confirmed. Gene and phenotype frequencies of Ko^a and Ko^b alloantigens are determined through a study of 254 Caucasians. Among 63 families, 26 informative families in a double back-cross situation made it possible to confirm that there is no close linkage between the Ko system and the HL-A, Rhesus, MNSs, Kell, Duffy and Lewis system.     

Cytotoxic Action of Pig Anti-A Erythrocyte Antibodies

Pig A blood group antigen was demonstrated on pig lymphocytes using the cytotoxic test. The typing of immune anti-A sera in the haemolytic test (against erythrocytes) and in the cytotoxic test (against lymphocytes obtained from the same animals) showed that reactions of both antibody families were identical. The results were confirmed by absorption studies.     

Anti-B4-blocked ricin synergizes with doxorubicin and etoposide on multidrug-resistant and drug-sensitive tumors

Anti-B4-blocked ricin (anti-B4-bR) is an immunotoxin directed against CD19-positive cells that is currently being tested in several B-cell leukemia/lymphoma clinical trials. To explore the possibility of using anti-B4-bR in combination with chemotherapy protocols, we investigated the in vitro and in vivo cytotoxic effects of combining it with doxorubicin or etoposide using the lymphoma cell line Namalwa and a P- glycoprotein-expressing cell line, Namalwa/mdr-1, obtained by retroviral infection of Namalwa cells with the mdr-1 gene. Namalwa/mdr- 1 cells were slightly more sensitive to anti-B4-bR than Namalwa cells; IC37 values were approximately 4 pmol/L and 8 pmol/L, respectively. When anti-B4-bR was combined simultaneously with doxorubicin or etoposide, additive to supra-additive killing of Namalwa and Namalwa/mdr-1 cells was observed. In xenografts of Na-malwa/mdr-1 cells in severe combined immunodeficiency (SCID) mice, doxorubicin and etoposide at their maximum tolerated doses (3 mg/kg x 3 or 15 mg/kg x 3) showed no therapeutic effect. However, treatment with 5 daily bolus injections of anti-B4-bR (50 micrograms/kg) followed by treatment with doxorubicin or etoposide significantly increased the life span of the mice by 129% and 115%, respectively. After treatment with anti-B4-bR, the Namalwa/mdr-1 population expressed lower levels of P-glycoprotein, and this decrease may account for the synergistic action of the drug combinations. These results suggest that anti-B4-bR could be used to good effect in combination with current treatment regimens and further hint at a promising role for this immunotoxin in treatment of disease at the minimal residual disease stage, where cells may be resistant to chemotherapy.