S M MacDonald

Bio: S M MacDonald is an academic researcher from University of Oxford. The author has contributed to research in topics: Monoclonal antibody & Antigen. The author has an hindex of 3, co-authored 3 publications receiving 3319 citations.

Immunoenzymatic labeling of monoclonal antibodies using immune complexes of alkaline phosphatase and monoclonal anti-alkaline phosphatase (APAAP complexes).

Abstract: A murine monoclonal antibody specific for calf intestinal alkaline phosphatase has been prepared and used in an unlabeled antibody bridge technique for labeling monoclonal antibodies. This procedure--the alkaline phosphatase monoclonal anti-alkaline phosphatase (APAAP) method--gives excellent immunocytochemical labeling of tissue sections and cell smears, comparable in clarity and intensity to that achieved with immunoperoxidase labeling. If the enzyme label is developed with a naphthol salt as a coupling agent and Fast Red or hexazotized new fuchsin as a capture agent, a vivid red reaction product is obtained which is very easily detected by the human eye. For this reason the APAAP technique was found particularly suitable for labeling cell smears (for both cytoplasmic and surface-membrane antigens) and for detecting low numbers of antigen-bearing cells in a specimen (e.g., carcinoma cells in a malignant effusion). It was found possible to enhance the intensity of the APAAP labeling reaction substantially by repeating the second and third incubation steps (i.e., the unlabelled "bridge" antibody and APAAP complexes). The APAAP technique was superior to immunoperoxidase labeling for staining tissues rich in endogenous peroxidase, and could be used in conjunction with immunoperoxidase methods for double immunoenzymatic staining. The method was also applicable to the detection of antigenic molecules following their electrophoretic transfer from SDS-polyacrylamide gels to nitrocellulose sheets ("immunoblotting").

A new monoclonal antibody (KB61) recognizing a novel antigen which is selectively expressed on a subpopulation of human B lymphocytes.

Abstract: The present paper describes a new monoclonal antibody (KB61) raised against hairy cell leukaemia cells. Antibody KB61 recognizes a molecule of approximately 40,000 molecular weight on human B cells. It reacts with B lymphocytes in the peripheral blood, in primary lymphoid follicles, in the mantle zone of secondary follicles, in interfollicular areas and in splenic marginal zone areas. However, germinal centre lymphoid cells do not express the antigen recognized by antibody KB61. The antibody shows limited reactivity outside the lymphoid system, i.e. polymorphs, tissue macrophages endothelial cells in the hepatic sinusoids. Antibody KB61 discriminates between different types of B-cell malignancies, reacting with the neoplastic cells in hairy cell leukaemia, chronic lymphocytic leukaemia (of B-cell type), prolymphocytic leukaemia and centrocytic lymphoma, but not with acute lymphoblastic leukaemia, germinal centre-derived lymphomas (other than centrocytic), Burkitt's lymphoma and lymphoblastic lymphoma. Antibody KB61 may be of value in the study of B-cell subpopulations and in the differential diagnosis of B-cell neoplasms.

A monoclonal antibody recognizing the p150/95 leucocyte differentiation antigen.

Abstract: A monoclonal antibody KB90 recognizing a molecule containing two polypeptide subunits of 140 and 98 kd is described Biochemical studies following high pH dissociation of the molecule showed KB90 to bind to an epitope on the 140 kd subunit The molecule recognized by KB90 appears to correspond to the p150/95 molecule in the family of leucocyte differentiation antigens of which the LFA-1 and Mac-1 molecules are members Analysis of the immunocytochemical reactivity of KB90 shows that it stains monocytes, tissue macrophages, granulocytes and a small population of lymphocytes These reactions are clearly distinct from those of the LFA-1 and Mac-1 molecules

Male infertility and the human microbiome

Abstract: The historical belief in urology was that the genitourinary system should be sterile in a normal, healthy, asymptomatic adult. This idea was perpetuated for decades until research revealed a diverse microbiota existing in human anatomical niches that contributed to both human health and disease processes. In recent years, the search for an etiology and modifiable risk factors in infertility has turned to the human microbiome as well. Changes in the human gut microbiome have been associated with changes in systemic sex hormones and spermatogenesis. Certain microbial species are associated with higher levels of oxidative stress, which may contribute to an environment higher in oxidative reactive potential. Studies have demonstrated a link between increased oxidative reactive potential and abnormal semen parameters in infertile men. It has also been hypothesized that antioxidant probiotics may be able to correct an imbalance in the oxidative environment and improve male fertility, with promising results in small studies. Further, the sexual partner's microbiome may play a role as well; studies have demonstrated an overlap in the genitourinary microbiomes in sexually active couples that become more similar after intercourse. While the potential applications of the microbiome to male fertility is exciting, there is a need for larger studies with uniform microbial sequencing procedures to further expand this topic.

CD40 ligand on activated platelets triggers an inflammatory reaction of endothelial cells

Abstract: CD40 ligand (CD40L, CD154), a transmembrane protein structurally related to the cytokine TNF-alpha, was originally identified on stimulated CD4+ T cells, and later on stimulated mast cells and basophils. Interaction of CD40L on T cells with CD40 on B cells is of paramount importance for the development and function of the humoral immune system. CD40 is not only constitutively present on B cells, but it is also found on monocytes, macrophages and endothelial cells, suggesting that CD40L has a broader function in vivo. We now report that platelets express CD40L within seconds of activation in vitro and in the process of thrombus formation in vivo. Like TNF-alpha and interleukin-1, CD40L on platelets induces endothelial cells to secrete chemokines and to express adhesion molecules, thereby generating signals for the recruitment and extravasation of leukocytes at the site of injury. Our results indicate that platelets are not only involved in haemostasis but that they also directly initiate an inflammatory response of the vessel wall.

Identification of tissue transglutaminase as the autoantigen of celiac disease

Abstract: Celiac disease is characterized by small intestinal damage with loss of absorptive villi and hyperplasia of the crypts, typically leading to malabsorption. In addition to nutrient deficiencies, prolonged celiac disease is associated with an increased risk for malignancy, especially intestinal T-cell lymphoma. Celiac disease is precipitated by ingestion of the protein gliadin, a component of wheat gluten, and usually resolves on its withdrawal. Gliadin initiates mucosal damage which involves an immunological process in individuals with a genetic predisposition. However, the mechanism responsible for the small intestinal damage characteristic of celiac disease is still under debate. Small intestinal biopsy with the demonstration of a flat mucosa which is reversed on a gluten-free diet is considered the main approach for diagnosis of classical celiac disease. In addition, IgA antibodies against gliadin and endomysium, a structure of the smooth muscle connective tissue, are valuable tools for the detection of patients with celiac disease and for therapy control. Incidence rates of childhood celiac disease range from 1:300 in Western Ireland to 1:4700 in other European countries, and subclinical cases detected by serological screening revealed prevalences of 3.3 and 4 per 1000 in Italy and the USA, respectively. IgA antibodies to endomysium are particularly specific indicators of celiac disease, suggesting that this structure contains one or more target autoantigens that play a role in the pathogenesis of the disease. However, the identification of the endomysial autoantigen(s) has remained elusive. We identified tissue transglutaminase as the unknown endomysial autoantigen. Interestingly, gliadin is a preferred substrate for this enzyme, giving rise to novel antigenic epitopes.

Cytoplasmic Nucleophosmin in Acute Myelogenous Leukemia with a Normal Karyotype

Abstract: Background Nucleophosmin (NPM), a nucleocytoplasmic shuttling protein with prominent nucleolar localization, regulates the ARF-p53 tumor-suppressor pathway. Translocations involving the NPM gene cause cytoplasmic dislocation of the NPM protein. Methods We used immunohistochemical methods to study the subcellular localization of NPM in bone marrow–biopsy specimens from 591 patients with primary acute myelogenous leukemia (AML). We then correlated the presence of cytoplasmic NPM with clinical and biologic features of the disease. Results Cytoplasmic NPM was detected in 208 (35.2 percent) of the 591 specimens from patients with primary AML but not in 135 secondary AML specimens or in 980 hematopoietic or extrahematopoietic neoplasms other than AML. It was associated with a wide spectrum of morphologic subtypes of the disease, a normal karyotype, and responsiveness to induction chemotherapy, but not with recurrent genetic abnormalities. There was a high frequency of FLT3 internal tandem duplications and absen...