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Lactic acid bacteria (lab)

  1. Lactic acid bacteria (LAB) By Mehwish Manzoor
  2. Contents... • Lactic acid bacteria (LAB) • Potential biomedical LAB applications • LAB as Vaccines • Steps of medical translation of live L. lactis-based vaccines • Benefits of LAB based Vaccines • Future perspectives
  3. Lactic acid bacteria (LAB) • Represent a group of different gram-positive microorganisms, • non sporulating bacteria • This group is distinguished by the ability to carry out • fermentation of carbohydrates to form lactic acid • Beneficial role played by these microorganisms in the humans and other animals
  4. Cont…….. • Present in many foods and are frequently used as probiotics • to improve some biological functions in the host
  5. Lactic Acid Bacteria (LAB) or Lactics applications • plants, meat, and dairy • Dairy products - acidophilus milk, yogurt, buttermilk, and cheeses • The Lactics are also important commercially in the processing of meats (sausage, cured hams), alcoholic beverages (beer, fortified spirits), and vegetables (pickles, and saukerkraut).
  6. Potential biomedical LAB applications • LAB as adjuvants, • immunostimulators, or • Therapeutic drug delivery systems • Factories to produce therapeutic molecules
  7. Why we choose LAB as vaccines? • Lactobacillus genus, are able to colonise cavities such as the mouth, the urogenital or the gastrointestinal tracts, where they play a critical role in maintaining a balanced normal micro flora • Preventing or lowering the incidence or recurrent urinary or digestive tract infections
  8. Cont….. • LAB are quite acid resistant and certain strains are able to effectively survive passage through the stomach • • Absence of LPS in their cell wall virtually eliminates the risk of • endotoxic shock
  9. Lactic acid bacteria (LAB) • Important genera of (LAB) Lactococcus, Lactobacillus, Leuconostoc, Streptococcus and Pediococcus. • Therapeutically used species L. acidophilus , L. brevis, L. casei, L. bulgaricus and L. bifidus.
  10. Exploitation of LAB • Live vaccine or vaccine delivery vehicle • The evolution of genetic engineering techniques • Expressing heterologous proteins in different cellular compartments • improving their antigenic potential for the production of vaccines against viruses, bacteria, and parasites.
  11. LAB as vaccine delivery vehicle • The use of bacteria as vaccine delivery vehicles implies construction of recombinant strains that contain the gene cassette encoding the antigen • Several genera of LAB are being tested as vaccine delivery vehicles
  12. Cont…… • Vaccines deliver vehicle • Expresses an antigen from another species • The vaccine component to be delivered can be either protein or DNA • Use of live viral or bacterial vectors for the production of replicative particulate antigens in vivo
  13. LAB as live vaccine • As Live bacterial vaccines • Designed to induce an immune response Itself • To develop LAB as live vaccines, they have to be genetically transformed
  14. Recent developments • Lactococcus lactis - Brucella abortis and Helicobacter pylori • Streptococcus gordonii prototype vaccines against HIV and measles • With Lactobacillus, prototype vaccines against anthrax and rotavirus are under development, and have already been obtained against tetanus
  15. Benefits of LAB based Vaccines • Eg: Lactococcus lactis • Lactococcus lactis is a GRAS (generally regarded as safe) bacterium that is widely used in the food industry • Intensive genetic and molecular research potential new biomedical applications –vaccine delivery, –gene delivery, –heterologous protein expression and – therapeutic drug delivery
  16. Future perspectives • No or few lactococcal vaccine candidates are currently under clinical investigation • The use of biological containment strategies may be necessary to prevent survival of genetically modified vaccine strains in the environment • The ultimate aim will be to develop environmentally safe, multi-valent LAB vaccine vectors against a variety of different pathogens