Immunology
Immunodeficiencies (AIDS) Vaccine
Enzyme-linked immunosorbent assays (ELISA) Hypersenstivity
Transplantation
Pricipal i/c
Department of Biochemistry
Bharathidasan University ModelCollege, Vedharanyam.
Dr. P. MURUGAN, M.Sc., M.Phil., Ph.D.,
Immunodeficiencies (AIDS)
1. HIV gp120 binds to CD4 on target cell.
3. Nucleocapsid containing viral genome and enzymes enters cells.
4. Viral genome and enzymes are released following removal of core proteins.
5. Viral reverse transcriptase catalyzes reverse transcription of ssRNA, forming RNA–DNA hybrids.
6. Original RNA template is partially degraded by ribonuclease H, followed by synthesis of second DNA strand to yield HIV dsDNA.
2. Fusogenic domain in gp41 and CXCR4, a G-protein–linked receptor in the target-cell membrane, mediate fusion.
7. The viral dsDNA is then translocated to the nucleus and integrated
into the host chromosomal DNA by the viral integrase enzyme.
Vaccine
DNA Vaccines
Production of vaccinia vector vaccine.
ELISA zyme-linked immunosorbent assays
(ELISA)
Sandwich ELISA
Fluorescent in situ hybridization
Fluorescent in situ hybridization (FISH) is a powerful technique for detecting RNA or DNA sequences in cells, tissues, and tumors. FISH provides a unique link among the studies of cell biology, cytogenetics, and molecular genetics.
In Situ Hybridization (ISH) uses a labeled probe to detect and localize specific RNA or DNA sequences in a tissue or on a chromosome.
Fluorescent" means emitting light that comes from a reaction within the emitter. "In situ" refers to the fact that this techniques is done with the chromosomes, cells or tissue in place (in situ) on a microscope slide.
Fluorescent in situ hybridization is a technique in which single-
stranded nucleic acids (usually DNA, but RNA may also be used) are permitted to interact so that complexes, or hybrids, are formed by molecules with sufficiently similar, complementary sequences.
The method comprises of three basic steps: fixation of a specimen on a microscope slide, hybridization of labeled probe to homologous
fragments of genomic DNA, and enzymatic detection of the tagged target hybrids. While probe sequences were initially detected with isotopic reagents, nonisotopic hybridization has become increasingly popular, with fluorescent hybridization now a common choice.
The detection of sequences on the target chromosomes is performed indirectly, commonly with biotinylated or
digoxigenin-labeled probes detected via a fluorochrome- conjugated detection reagent, such as an antibody
conjugated with fluorescein. As a result, the direct visualization of the relative position of the probes is possible.
FISH is a very general technique. The differences between the various FISH techniques are usually due to variations in the sequence and labeling of the probes; and how they are used in combination. These few modifications make possible all FISH techniques.
Probe size is important because longer probes hybridize
more specifically than shorter probes.
Medical applications
In medicine, FISH can be used to form a diagnosis, to evaluate prognosis, or to evaluate remission of a disease, such as cancer.
FISH can also be used to detect diseased cells more easily than standard Cytogenetic methods .
FISH, does not require living cells and can be quantified
automatically, a computer counts the fluorescent dots present.
FISH can be used to detect directly the presence of the microbial pathogens on small samples of patient's tissue.
FISH can also be used to compare the genomes of two biological species, to deduce evolutionary relationships.
Hypersensitive Reactions
General mechanism underlying a type I hypersensitive reaction.
General mechanism underlying a type I hypersensitive reaction.
Type 1
Asthma
Antibody-Mediated Cytotoxic (Type II) Hypersensitivity
Type II
Immune Complex–Mediated (Type III) Hypersensitivity
Type III
Type IV or Delayed-Type Hypersensitivity (DTH)
Type IV
Type IV
