ABSTRACT
In this study, phosphatidylethanol formed by phospholipase D catalysed transphosphatidylation of phosphatidylcholine was employed as a component for preparation of liposomal carrier for oral delivery of insulin. Thermotropic behaviour of liposomes from mixtures of dipalmitoyl phosphatidylcholine and dipalmitoyl phosphatidylethanol, and their resistance to pancreatic phospholipase A(2) catalysed hydrolysis were studied. Three kinds of liposomes with insulin were prepared to examine the pharmacological availability of liposomes with phosphatidylethanol: (i) dipalmitoyl phosphatidylcholine/dipalmitoyl phosphatidylethanol (1:1 w/w) liposomes; (ii) dipalmitoyl phosphatidylcholine/dipalmitoyl phosphatidylethanol/palmitoyl-stearoyl sucrose (1:1:0.2) liposomes; and (iii) liposomes composed of natural phosphatidylcholine and phosphatidylinositol (1:1). The resultant liposomes were orally administrated to rats with blood glucose concentration of 270 mg/100 ml in a dose of 12 IU/kg body weight. Blood samples were collected 0.5, 1.5, 3, 5, and 24 h after treatment. Oral administration of all liposomal species resulted in hyperinsulinemia. Hyperinsulinemia induced by liposomes containing dipalmitoyl phosphatidylethanol was attended by a decrease of blood glucose concentration. No correlation between insulin level and glucose concentration in the rat blood after oral administration of phosphatidylinositol-containing liposomes was observed.
Subject(s)
Chemistry, Pharmaceutical , Diabetes Mellitus, Experimental/drug therapy , Glycerophospholipids/chemistry , Hypoglycemic Agents/administration & dosage , Insulin/administration & dosage , Phospholipases A/chemistry , Administration, Oral , Animals , Calorimetry, Differential Scanning , Drug Carriers , Hydrolysis/drug effects , Hypoglycemic Agents/therapeutic use , Insulin/therapeutic use , Liposomes , Male , Rats , Rats, WistarABSTRACT
Antibiotic entrapment to liposomes containing phosphatidyl ethanol, a negatively charged phospholipid, as a lipid component was studied. Antibiotics of various groups such as doxorubicin, rifampicin and doxycycline were entrapped to liposomes consisting of a mixture of phosphatidyl choline and phosphatidyl ethanol at a ratio of 1:1 (v/v) or phosphatidyl choline alone. It was shown that the liposomes containing phosphatidyl ethanol were able to entrap the antibiotics in higher amounts by comparison with the liposomes containing phosphatidyl choline. Phosphatidyl ethanol in the composition of the liposomes had the highest effect on the entrapment of doxorubicin.
Subject(s)
Anti-Bacterial Agents/administration & dosage , Glycerophospholipids , Liposomes/chemistry , Phosphatidic Acids/analysis , Doxorubicin/administration & dosage , Doxycycline/administration & dosage , Drug Carriers , Molecular Structure , Phosphatidylcholines/analysis , Rifampin/administration & dosageABSTRACT
A set of synthetic peptides derived from the capsid protein of hepatitis A virus was used to search for B-epitopes. Peptides from the 115-139 region of the VP1 protein, from the 69-99 region of the VP2 protein and peptide 137-150 from the VP3 protein were found to react with monoclonal and polyclonal anti-HAV antibodies. MAPs based on 64-80 and 66-80 fragments of VP3 were reactive as well. Peptides, their conjugates with protein carriers and MAPs were used for antipeptide antibody production. Only free peptide 69-99 from the VP2 protein caused formation of HAV binding antibodies.
Subject(s)
Capsid/chemistry , Hepatovirus/chemistry , Amino Acid Sequence , Animals , Antibody Formation , Epitopes/chemistry , Hepatovirus/immunology , Mice , Mice, Inbred BALB C , Molecular Sequence Data , Peptides/chemical synthesisABSTRACT
Monoclonal and polyclonal anti-hepatitis A (HAV) antibodies were used to search for peptides mimicking the antigenic determinants of HAV. Synthetic peptides VP1 115-139, VP1 117-139, VP1 126-139, VP2 69-99, VP2 80-99, VP3 45-57, VP3 137-150, were shown to bind the anti-HAV antibodies in ELISA. Peptides VP1 115-139, VP1 117-139, VP2 69-99 were utilized to produce the antipeptide antibodies. Mice were immunized with the free peptides or with their conjugates with ovalbumin. Only the free VP2 69-99 caused formation of HAV binding antibodies.
Subject(s)
Epitopes/chemistry , Hepatovirus/immunology , Peptides/chemistry , Amino Acid Sequence , Animals , Antibodies, Monoclonal/immunology , Enzyme-Linked Immunosorbent Assay , Mice , Models, Molecular , Molecular Sequence DataABSTRACT
Computer search for probable T-epitopes of hepatitis A virus capsid proteins was performed using an integrated set of programs. Eight segments of the VP1, VP2, VP3 and VP4 proteins were chosen and synthesised. Five peptides previously examined as probable B-epitopes were used as well. All the peptides were tested for their ability to stimulate proliferation of lymph node T-cells primed with synthetic peptides. Almost all predicted T-epitopes affected the T-cell proliferation. None of the peptides had mitogenic activity. We demonstrated that regions 17-33 and 276-298 of VP1 are possible immunodominant promiscuous sites activating lymphocytes of all mouse haplotypes.
Subject(s)
Antigens, Viral/immunology , Epitopes/analysis , Hepatovirus/immunology , Lymphocyte Activation , Peptides/immunology , T-Lymphocytes/immunology , Amino Acid Sequence , Animals , Antigens, Viral/chemistry , Cells, Cultured , Crosses, Genetic , Female , Hepatitis A Antigens , Lymph Nodes/immunology , Male , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Mice, Inbred CBA , Molecular Sequence Data , Peptides/chemical synthesis , Peptides/chemistry , Protein Structure, SecondaryABSTRACT
Computer search for probable T-epitopes of the hepatitis A virus capsid proteins was performed using developed integrated set of programmes. The following peptides were chosen and synthesised by solid phase technique: 75-92 VP1, 115-139 VP1, 209-221 VP1, 69-99 VP2, 80-99 VP2, 45-57 VP3, 137-150 VP3 and 1-23 VP4. Peptides 1-17 VP1, 10-33 VP1, 11-25 VP1, 75-85 VP1 and 276-298 VP1 previously examined as probable B-epitopes were used as well. All the peptides were tested for their ability to stimulate proliferation of lymph node T-cells primed with synthetic peptides. Almost all the predicted T-epitopes did affected the T-cell proliferation. 10-33 VP1 and 276-298 VP1 stimulated lymph node proliferation of all tested mouse strains. 107-126 VP1 and 115-126 VP1 did not influence proliferation of lymphocytes of mice primed with these peptides but stimulated proliferation of T-cells of F1 (CBA x C57Bl6) mice primed with 115-139 VP1.
