This document summarizes the identification of lymphocytes and their subsets in blood. It discusses that lymphocytes are formed from hematopoetic stem cells and their main functions. The different types of lymphocytes - NK cells, T-lymphocytes, and B-lymphocytes - are identified based on the cluster of differentiation antigens they express. Flow cytometry using monoclonal antibodies for unique CD regions is used to identify and count the different lymphocyte subsets in a blood sample.

1. SEMINARON
IDENTIFICATIONO LYMPHOCYTESANDTHEIRSUBSETSIN
BLO
By:
Poornima R.
1ST M.Sc. Biotechnology

2. INTRODUCTION
Lymphocytes are formed by hematopoetic stem cells.

3. Their common functions are
1. NK Cells:
Usually have cytotoxic activity against a wide range of
tumor cells and also against some cells infected with
viruses.
2. T-Lymphocytes
They identify and bind to antigenswhich are bound
to MHC complex,a self antigen on the surface of T-
cells.
3. B-Lymphocytes
Produce antibodies against a given antigen.The Abs
act as receptors.

4.  These cells are identified in blood depending on the
CD antigens [cluster of differentiation] expressed
characteristically, but not uniquely, by the cells of
certain lineage and certain stage of their
differentiation.
 Examples
Cd45RA and CD62L identify naive T-cells
CD45RO identifies memory B-cell
CD16 and CD56 idntify NK cells

6. Identification:
Monoclonal antibodies for unique CD regions is
synthesised and incubated with aliquotes of blood
sample.
Flow cytometry is used to identify and count the cells
using an automated fluorescence activated cell
scanner which measures the fluorescence generated by
each labelled cell.
Cells are aspirated into the machine and surrounded
by a sheath fluid, which forcs the cells to flow through
a chamber in single file past a beam laser and light
sensor.

7. Light emitted by the excited fluorescent dye on the cell
surface is detected by the sensor and analysed by
computer softwares.

8.  In total lymphocyte count
a. 60% to 70% is that of CD3+ T-cell
b. B-cells make upto ‹10 %
c. Remaining are NK cells.

9. REFERENCE
 Kuby immunology by
 Clinical immunology by Rabindra Narain
 Clinical immunology by Chapel,Haeney,Misbah and
Snowden