Here is some information about 5 important immunological techniques including Flowcytometry and RIA I hope it helps and please comment if u come across any mistakes or scope for improvement, it'll really be appreciated.

1. TECHNIQUES:
•FLOWCYTOMETRY
•IMMUNOFLUORESCENCE
•AGGLUTINATION INHIBITION
ASSAY
•RIA(RadioImmunoassay)
•RAST(Radioallergosorbent test)

2. FLOWCYTOMETRY
 Flow cytometry is a laser-based,
biophysical technique employed in cell
counting, cell sorting, biomarker
detection and protein engineering, by
suspending cells in a stream of fluid
and passing them by an electronic
detection apparatus.
 The flow cytometer uses a laser beam
and light detector to count single intact
cells in suspension.

3. A

4. Applications:
1.Determine the kind and number of white blood
cells in blood samples.
2. How many cells express the target antigen as
an absolute number and also as a percentage of
cells passing the beam.
3. The size of cells. This information is derived
from analysis of the light-scattering properties of
members of the cell population under
examination.

5. IMMUNOFLUORESCENCE
Fluorescent molecules absorb light of one
wavelength(excitation) and emit light of another
wavelength (emission).
If antibody molecules are tagged with a fluorescent dye,
or fluorochrome, immune complexes containing these
fluorescently labeled antibodies (FA) can be detected by
colored light emission when excited by light of the
appropriate wavelength.
The emitted light can be viewed with a fluorescence
microscope.
In this technique, fluorescent compounds such as
fluorescein and rhodamine are conjugated to the Fc
region of an antibody molecule without affecting the
specificity of the antibody.

6. Fluorescent-antibody staining of cell
membrane molecules or tissue sections
can be direct or indirect.
In direct staining, the specific antibody (the
primary antibody) is directly conjugated
with fluorescein.
In indirect staining, the primary antibody is
unlabeled and is detected with an
additional fluorochrome-labeled reagent.

7. X

8. ADVANTAGES OF INDIRECT
OVER DIRECT:
1. The primary antibody does not need to be
conjugated with a fluorochrome. As the supply of
primary antibody is often a limiting factor, indirect
methods avoid the loss of antibody that usually
occurs during the conjugation reaction.
2. Indirect methods increase the sensitivity of
staining because multiple molecules of the
fluorochrome reagent bind to each primary
antibody molecule.

9. APPLICATIONS:
1.Identifification a number
of subpopulations of lymphocytes, notably the
CD4
and CD8 T-cell subpopulations.
2. Detecting Ag-Ab complexes in autoimmune
disease.
3. Localization of antigens in tissue sections or
in sub cellular compartments.

10. AGGLUTINATION INHIBITION
ASSAY
A modification of the agglutination reaction, called
agglutination inhibition, provides a highly sensitive
assay for small quantities of an antigen.
In this assay the presence or absence of an
antigen can be determined based on the formation
of agglutination or not.
For example it was used in early pregnancy kits
and also to find out if a person is on certain kind of
drugs.

12. APPLICATIONS:
1.Pregnancy test
2.To test presence of certain drugs in
the body
3.Exposure to certain
viruses(hemagglutination test).

13. RADIOIMMUNOASSAY
The principle of RIA involves competitive binding
of radiolabeled antigen and unlabeled antigen to
a high-affinity antibody.
The labeled antigen is mixed with antibody at a
concentration that saturates the antigen-binding
sites of the antibody.
Then test samples of unlabeled antigen of
unknown concentration are added in
progressively larger amounts.

15. USES:
RIA is widely used for
measuring hormones, serum
proteins, drugs, and vitamins at
concentrations of 0.001
micrograms per milliliter or less.

16. RAST
It detects the serum level of IgE specific for a
given allergen.
The allergen is coupled to beads or disks, the
patient’s serum is added, and unbound antibody
is washed away.
The amount of specific IgE bound to the solid-
phase allergen is then measured by adding 125I
labeled rabbit anti-IgE, washing the beads, and
counting the bound radioactivity

17. RAST can quantify nanogram amounts of
serum IgE specific for a particular allergen.

18. Contrary to RIST, this method
is used to detect specific IgE
antibodies, to determine the
substance a subject is allergic
to.
In RIST the total serum IgE
levels are determined.