Lectins are involved in recognition phenomena and their ability to bind particular Carbohydrate structures are the key to their biological functions. Bacteria typically attaches to prospective host cell membranes in receptors with lectin like sugar specificity. This is of great importance as the adherence of bacteria to host tissue surfaces is the initial event in bacterial infection. Lectins are also known to play important roles in immune system by recognizing carbohydrates that are found exclusively on pathogens, or that are inaccessible on host cells. This ability of lectins to selectively bind or agglutinate specific sugars have made them useful tools for the characterization of certain cell types or fragments, to detect cells in different states of development, to distinguish normal from tumour cells and to separate different cell types by affinity chromatography. A total of 120 samples of local Achatina achatina snail specie were collected, authenticated at the Zoology Department of the University of Nigeria, Nsukka and 80mls of pooled crude Lectin extract was obtained. Purifications were performed on 20mls of the crude extract in three steps viz, Ammonium sulphate precipitation and Dialysis (Partial purifications), Con A Sepharose 4B affinity chromatography column (Complete purification). The affinity purified lectin was used in all the tests conducted in this research. The crude, partially and complete/affinity purified lectin extracts were subjected to Haemagglutination and Protein Assay tests. The Molecular weight was deduced by Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) method. The microbial agglutination potentials of the lectin was assessed by testing typed bacterial organisms viz, Salmonella typhimurium, Escherichia coli, Lactobacilli acidophilus, Pseudomonas aeruginosa, Staphylococcus aureus, Klebsiella aeruginosa and four typed fungal organisms: Aspergillus niger, Trichophyton mentagrophytes, Candida albicans and A. flavus. The lectin’s Lymphocyte blastogenesis activities was determined by its incubation with human lymphocytes for mitogenic stimulation assay. The results of the research showed as follows: On complete/affinity purification, 15mls of pure sample containing only the high molecular weight lectin was obtained. On standardization, the respective haemagglutination tests on the crude, partially and affinity purified lectin showed preferential agglutinations with Blood group A type. Only S. typhimurium (+++), E. coli (+) and L. acidophilus (+) reacted with the lectin but in different strengths. Incubation of the lectin with lymphocytes from human serum showed that it has the ability to stimulate lymphocytes to undergo mitosis. This research has therefore succeeded in assessing the Microbial agglutination and Lymphocyte blastogenesis potentials of the isolated and characterised A. achatina snail lectin.
The distinguishing characteristics of the plasma membrane are its exposed proteins
