The document presents a comprehensive overview of interferons, small proteins produced by virus-infected cells that play a crucial role in antiviral defense and immune response. It covers their discovery, types (including IFN-α, IFN-β, and IFN-γ), mode of action, and various applications in treating conditions like cancer and hepatitis C. Additionally, it mentions potential side effects and outlines the biochemical mechanisms through which interferons exert their effects in the body.

1. GOVt. Nagarjuna PG college of science, Raipur
Presentation by Submitted to
Chandrakant Department of microbiology
Topic – interferons

2. Interferons

3. Synopsis
• Introduction
• Descovery
• What are interferons
• General action of interferons
• Types of interferons
• Mode of action
• Application
• Side effect of interferons
• Reference

4. Introduction
• Interferon are small proteins released by macrophages ,
lymphocytes , and tissue cells infected with virus .
• Interferon are set of proteins which are released by virus infected
cells and which reacts with uninfected cells so as to render them
resistant to infection to virus .

5. Discovery of Interferons
• 1957
• Alice Isaacs and jean Lindeman
• Did an experiment using chicken cell cultures
• Found a substance that interfered with viral
replication and was therefore named interferon

6. What are Interferons?
• Interferons (IFNs) are a family of cytokines that were first
identified almost half a century ago through their antiviral
properties.
• IFNs(.α , β and γ)are types of cytokines .there are 2 major
classes of IFNs
• in particular IFN –α (produced by a cell following viral
(major ) or bacterial infection.
• Interferons are proteins produced by a variety of cells in
the inflammatory response to infections ,their production is
triggered by the immune system in response to pathogens
or cytokines.
• Endogenous IFNs play a role in viral infections.

7. • Research suggests that IFNs may also be beneficial in the treatment
of other viral autoimmune, and neoplastic conditions of the nervous
system.
• IFN- γ Plays important role in controlling disease caused by
intracellular bacteria, parasites, and fungi by induction of reactive
oxidant species.
• The interferons are the classic example of the two-edged sword .on
one side , they have a remarkable ability to promote both innate and
acquired responses to viral infections.

8. • General action of interferons
IFNs are small proteins release by macrophages,
lymphocytes, and tissue cells infected with virus.
When a tissue cell is infected by a virus, it releases
interferons. Interferons diffuse to the surrounding
cells. When it binds to receptors on the surface of
those adjacent cells, they begin the production of
protein that prevents the synthesis of viral proteins.this
prevents the spread of the virus throughout the body.

10. Types of interferons
S.no. Types Source
1. α - Interferons Monocytes and
lymphocytes
2. β- Interferons Fibroblasts and epithelial
cells
3. γ - Interferons T-cells

11. • Type 1 interferons (IFN - α and IFN - β ) which
mediated earl antiviral response.(IFN- α
produced/ released by leukocytes and IFN - β by
fibroblast.)
Type 1 interferons

12. Type 2 interferons
• The type 2 interferons(such as IFN -γ ) , which
activate macrophages, interact with cells of the
adaptive immune system,and support the generation
of T1 cells(produced by T-cells and cytotoxic
natural killer (NK) cells

13. Type 3 interferons
• The type 3 interferons (IFN- λ ),which are secreted
by plasmacytoid dendritic cells and regulate viral
replication and host cell proliferation ( secreted by
DC cell called plasmacytoid cell.

14. Mode of action
• IFN –α and IFN – β exert their antiviral and other effects by binding
to a specific receptor called IFNAR (interferons alpha receptor)that
is expressed by most cell types .
• Like many cytokines IFNs are dimers binding of the IFN dimer to
IFNR induces receptor dimerization and activation of the JAK
/STAT signaling pathway used by many cytokines to activate
specific responses.
• The IFNAR dimer activates the Janus kinase JAK1 and TYK2
which recruit and phosphorylate inactive STAT transcription
factors.
• Interferons α and β bind to and dimerize IFNAR(the interferons
alpha receptor), which then recruits and activate the JAK 1 and
TYK2 protein kinases.

15. • Thy bind and phosphorylate STAT 1 and STAT 2, which
dimerize enter the nucleus and stimulate expression of protein
that activate antiviral effects.
• Protein kinase R(PkR)binds viral dsRNA and inhibits the activity
of the elF2a translation inhibition factor.
• 2’5’-oligodenylate , which activates a ribonuclease RNase L,that
degrades viral and cellular mRNAs.
• MX proteins self –assemble into like structures that inhibit viral
replication and the formation of new viral particles.
• IFIT proteins inhibit of new viral proteins by binding to viral
RNA and to elF3 a translation inhibition factor.

17. APPLICATIONS AND
PHARMACEUTICAL USES
• USED IN COMBINATION WITH CHEMOTHERAPY
AND RADIATION AS A TREATMENT FOR
CANCERS.
• TREATMENT AND CONTROL OF MULTIPLE
SCLEROSIS.
• PEGYLATED INTERFERONα IN COMBINATION
WITH THE ANTIVIRAL DRUG RIBAVIRIN IS USED
IN TREATMENT OF HEPATITIS C.

18. • Common side effects include:-
1. Fever
2. Fatigue
3. Muscular pains
4. Local inflammation
• High levels of interferons can cause kidney, liver,
bone marrow and heart toxicity

19. Reference
• Immunology book by anumugam and dulsy
Fatima .