Investigation of hypogycemic and hypolipidemic effects of an aqueous extract of Llupinus albus legume seed in Streptozotocin-induced type I diabetic rats

Background: Lupinus albus (LA) seed is a legume food used traditionally for the treatment of diabetes. The aim of this study was to investigate the effects of an aqueous extract of LA on lipid and glucose levels in normal and STZ induced Type 1 diabetic rats.Methods: Aqueous extract of LA was prepared and used for animal treatments. Diabetes was induced by a single intraperitoneal injection of streptozotocin (60mg/kg body weight). Effects of LA on oral glucose tolerance in normal and diabetic rats were investigated by giving a single dose of distilled water (controls), 200 or 400mg/kg LA extract, metformin 300mg/kg or glibenclamide 500μg/kg after 12 hours of fasting (time 0 glucose). After 15 minutes, a glucose load (3g/kg) was given. Glucose levels were measured at 30, 60, and 120 minutes after glucose loading. To investigate long term effects, animals were given similar treatments daily for 4 weeks. At the end of the study, serum glucose, insulin, total cholesterol (TC), triglycerides (TG), low density lipoprotein (LDL-C), very low density lipoprotein (VLDL-C) and high density lipoprotein (HDL-C) cholesterol levels were measured or calculated.Results: LA demonstrated significant (P<0.001) hypoglycaemic effects in normal rats but not in diabetic rats after acute and long term treatment. Normal LA treated rats showed higher (P<0.001) insulin levels compared to normal controls but insulin remained very low in diabetic rats. Diabetic rats showed diabetes associated weight loss in both treated and untreated rats. However, LA was effective in reducing atherogenic lipid levels (TC, TG, LDL-C VLDLC; P<0.001) with no change (P>0.05) in HDL-C.Conclusion: We conclude that the use of Lupinus albus among various communities may not be effective in treating hyperglycaemia in type 1 diabetes but effective for treating diabetes induced dyslipidemia.Key words: glucose tolerance, lipids, Lupinus albus, streptozotocin, type 1 diabetes

Escape from recognition of SARS-CoV-2 Beta variant spike epitopes but overall preservation of T cell immunity

SARS-CoV-2 variants have emerged that escape neutralization and potentially impact vaccine efficacy. T cell responses play a role in protection from reinfection and severe disease, but the potential for spike mutations to affect T cell immunity is incompletely understood. We assessed neutralizing antibody and T cell responses in 44 South African COVID-19 patients infected either with the Beta variant (dominant from November 2020 to May 2021) or infected prior to its emergence (first wave, Wuhan strain), to provide an overall measure of immune evasion. We show that robust spike-specific CD4 and CD8 T cell responses were detectable in Beta-infected patients, similar to first wave patients. Using peptides spanning the Beta-mutated regions, we identified CD4 T cell responses targeting the wild type peptides in 12/22 first wave patients, all of whom failed to recognize corresponding Beta-mutated peptides. However, responses to mutated regions formed only a small proportion (15.7%) of the overall CD4 response, and few patients (3/44) mounted CD8 responses that targeted the mutated regions. Among the spike epitopes tested, we identified three epitopes containing the D215, L18, or D80 residues that were specifically recognized by CD4 T cells, and their mutated versions were associated with a loss of response. This study shows that in spite of loss of recognition of immunogenic CD4 epitopes, CD4 and CD8 T cell responses to Beta are preserved overall. These observations may explain why several vaccines have retained the ability to protect against severe COVID-19 even with substantial loss of neutralizing antibody activity against Beta