1. IMMUNOMODULATORS

2. Definition
An immunomodulator is a substance(eg. a drug) which has an effect on the immune system.
2 types
Immunosuppressants
Immunostimulants

3. The Immune Response - why and how ?
Discriminate: Self / Non self
Destroy:
Infectious invaders
Dysregulated self (cancers)
Immunity:
Innate, Natural
Adaptive, Learned

5. Mechanisms of immunomodulation
Drugs may modulate immune mechanism by either suppressing or by stimulating one or more of the following steps:
Antigen recognition and phagocytosis
Lymphocyte proliferation/differentiation
Synthesis of antibodies
Ag –Ab interaction
Release of mediators due to immune response
Modification of target tissue response

6. The importance of immune system in protecting the body against harmful molecules is well recognized
However, in some instances, this protection can result in serious problems
E.g, the introduction of allograft can elicit a damaging immune response causing rejection of the transplanted tissue
The transplant of an organ or tissue from one individual to another of the same species with a different genotype. For example, a transplant from one person to another, but not an identical twin, is an allograft. Allografts account for many human transplants, including those from cadaveric, living related, and living unrelated donors. Also known as an allogeneic graft or a homograft.

7. IMMUNOSUPPRESSANTS

8. IMMUNOSUPPRESSANTS The importance of the immune system
In protecting the body against harmful foreign molecules is well recognized.
However, in some instances, this protection can result in serious problems.
For example, the introduction of an allograft (that is, the graft of an organ or tissue from one individual to another who is not genetically identical) can elicit a damaging immune response, causing rejection of the transplanted tissue.
Transplantation of organs and tissues (for example, kidney, heart, or bone marrow)
Has become routine due to improved surgical techniques and better tissue typing.
Also, drugs are now available that more selectively inhibit rejection of transplanted tissues while preventing the patient from becoming immunologically compromised.

9. Earlier drugs were nonselective
Patients frequently succumbed to infection due to suppression of both the antibody-mediated (humoral) and cell-mediated arms of the immune system.
Today, the principal approach to immunosuppressive therapy
To alter lymphocyte function using drugs or antibodies against immune proteins.
Because of their severe toxicities when used as monotherapy,
A combination of immunosuppressive agents, usually at lower doses, is generally employed.
Immunosuppressive drug regimens
Consist of anywhere from two to four agents
With different mechanisms of action that disrupt various levels of T-cell activation.

10. IMMUNE ACTIVATION CASCADE
A three-signal model.
Signal 1
Constitutes T-cell triggering at the CD3 receptor complex by an antigen on the surface of an antigen-presenting cell (APC).
Signal 2, also referred to as costimulation,
Occurs when CD80 and CD86 on the surface of apcs engage CD28 on T cells.
Both Signals 1 and 2
Activate several intracellular signal transduction pathways,
one of which is the calcium calcineurin pathway
Which is targeted by cyclosporine and tacrolimus.
These pathways trigger the production of cytokines such as interleukin (IL)-2, IL-15, CD154, and CD25.
IL-2 then binds to CD25 (also known as the IL-2 receptor) on the surface of other T cells to activate mammalian target of rapamycin (mTOR)
Providing Signal 3, the stimulus for T-cell proliferation.

11. IMMUNOSUPPRESSANT DRUGS
These categorized according to their MOA:
Some agents interfere with cytokine production or action (Calcineurin inhibitors/specific T-cell inhibitors)
Others disrupt cell metabolism, preventing lymphocyte proliferation (cytotoxic drugs)
Mono, and polyclonal antibodies block T cell surface molecules (antibodies)

12. IMMUNOSUPPRESSANT DRUGS CLASSIFICATION
Calcineurin inhibitors (specific T –cell inhibitors):
Cyclosporine, Tacrolimus
M-TOR inhibitors-
Sirolimus, Everolimus
3. Antiproliferative drugs (cytotoxic drugs)
Azathioprine, cyclophosphamide, methotrexate, chlorambucil, mycophenolate mofetil (MMF)
4. Glucocorticoids
Prednisolone and others

13. 5. Biological agents- TNFα inhibitors- IL-1 receptor antagonist:
Etanercept, Infliximab, Adalimumab
IL-1 receptor antagonist:
Anakinra, Rilonacept
IL-2 receptor antagonist:
Daclizumab, Baciliximab
Monoclonal antibodies-
Anti CD3 antibody:
Muromonab
Anti CD52 antibody:
Alemtuzumab
Polyclonal Antibodies:
Antithymocyte Antibody (Atg), Rho (D) immuneglobulin.

15. ///////////////////////
Philip F. Halloran:N Engl J Med 2004;351:

16. Immunosuppressants Problem Organ transplantation Autoimmune diseases
Life long use
Infection, cancers
Nephrotoxicity
Diabetogenic

17. SELECTIVE INHIBITORS OF CYTOKINE PRODUCTION AND FUNCTION
Cytokines are soluble, antigen-nonspecific, signaling proteins
That bind to cell surface receptors on a variety of cells.
The term cytokine includes the molecules known as
Interleukins (ILs), interferons (IFNs), tumor necrosis factors (TNFs), transforming growth factors, and colony-stimulating factors.
IL-2, a growth factor
That stimulates the proliferation of antigen-primed (helper) T cells
Which subsequently produce more IL-2, IFN-γ, and TNF-a.
These cytokines collectively activate
Natural killer cells, macrophages, and cytotoxic T lymphocytes.
Drugs that interfere with the production or activity of IL-2,
Such as cyclosporine, will significantly dampen the immune response and, thereby, decrease graft rejection.

19. CYCLOSPORINE Cyclic peptide composed of 11 aa
Extracted from a soil fungus
Selectively inhibit
T lymphocyte proliferation
IL-2 & other cytokine production
Response of inducer T cells to IL-1, without any effect on suppressor T cells.
Lymphocytes are arrested at G0 or G1 phase

20. MECHANISM OF ACTION
Cyclosporine preferentially suppresses cell mediated immune reactions
humoral immunity is affected to a far lesser extent.
After diffusing into the T cell,
Cyclosporine binds to a cyclophilin (called an immunophilin)
To form a complex that binds to calcineurin.
The latter is responsible for dephosphorylating NFATc (cytosolic Nuclear Factor of Activated T cells).
Because the cyclosporine-calcineurin complex cannot perform this reaction,
NFATc cannot enter the nucleus
To promote the reactions that are required for the synthesis of a number of cytokines, including IL-2.
The end result is a decrease in IL-2
Which is the primary chemical stimulus for increasing the number of T lymphocytes.

21. (Cytoplasmic Phosphatase)
Activated T cells produces IL2 via Dephosphorilation of NAFT (nuclear factor activated T cell - a cytoplasmic transcription factor)
Calceneurin is needed for dephosphorilation
(Cytoplasmic Phosphatase)
Translocates to nucleus
Transcriptin of IL2 gene.
Cyclosporine bind s to cyclophilin - binding protein.
Tacrolimus binds to FKBP – FK binding protein.

24. (nuclear factor activated T cell)

25. TOXICITY : CYCLOSPORINE
Renal dysfunction
Tremor
Hirsuitism (abnormal growth of hair on a woman's face and body.)
Hypertension
Hyperlipidemia
Gum hyperplasia (Increase in the size of the gingiva (gums).)
Hyperuricemia (abnormally high level of uric acid in the blood)- worsens gout
Calcineurin inhibitors + Glucocorticoids = Diabetogenic

26. USES
To prevent rejection of kidney, liver, cardiac, BM and other allogeneic transplants.
More effective when glucocorticoids are also admininistered.
Useful in autoimmune disease as well.
Alternative to methotrexate for the treatment of severe, active RA.
2nd line drug for uveitis, bronchial asthma, etc.

27. TACROLIMUS Structure-macrolide like
Chemically different from cyclosporine, newer immunosuppressant
Macrolide that is isolated from soil fungus
Mechanism
Similar to cyclosporine except binds to different protein FK-506 binding protein that inhibits calcineurin.
Inhibits synthesis and release of IL-2

28. CLINICAL APPLICATION
Approved for the prevention of rejection of liver and kidney transplants
Given with a corticosteroid and/or an antimetabolite.
Favor over cyclosporine, Because of
Its potency
Decreased episodes of rejection
Also lower doses of corticosteroids can be used
Thus reducing the steroid-associated adverse effects.

29. ADVERSE EFFECTS
Nephrotoxicity and neurotoxicity (tremor, seizures, and hallucinations)
Development of post transplant, insulin-dependent diabetes mellitus.
Other toxicities are the same as those for cyclosporine
Except that tacrolimus does not cause hirsutism or gingival hyperplasia.
Have a lower incidence of cardiovascular toxicities
Such as hypertension and hyperlipidemia
Anaphylactoid reactions to the injection vehicle.

30. M-TOR INHIBITORS-SIROLIMUS
Structure-macrolide like (Multi-membered lactone ring )
Triene macrolide antibiotic
From Streptomyces hygroscopicus

31. MECHANISM OF ACTION
Sirolimus and tacrolimus bind to the same cytoplasmic FK-binding protein
But instead of forming a complex with calcineurin
Sirolimus binds to mTOR, interfering with Signal 3.
The latter is a serine-threonine kinase.
TOR proteins are essential for
Many cellular functions, such as cell-cycle progression, DNA repair, and as regulators involved in protein translation.
Binding of sirolimus to mTOR
Blocks the progression of activated T cells from the G1 to the S phase of the cell cycle and, consequently, the proliferation of these cells.
Unlike cyclosporine and tacrolimus,
Sirolimus does not owe its effect to lowering IL-2 production but, rather, to inhibiting the cellular responses to IL-2.

33. ADVERSE EFFECTS A common adverse effect
Hyperlipidemia (elevated cholesterol and triglycerides)
The combination of cyclosporine and sirolimus
More nephrotoxic
Necessitating lower doses.
Other untoward problems are
Headache, nausea and diarrhea, leukopenia, and thrombocytopenia.
Impaired wound healing in obese patients and those with diabetes.

34. CLINICAL APPLICATION Approved for use in renal transplantation
To be used together with cyclosporine and corticosteroids.
The combination of sirolimus and cyclosporine
Synergistic
Because sirolimus works later in the immune activation cascade.
The antiproliferative action of sirolimus has found use in cardiology.
Sirolimus-coated stents inserted into the cardiac vasculature
Inhibit restenosis of the blood vessels by reducing proliferation of the endothelial cells.
In addition to its immunosuppressive effects
Also inhibits proliferation of cells in the graft intimal areas
Thus, is effective in halting graft vascular disease.

35. EVEROLIMUS Another mTOR inhibitor, MECHANISM OF ACTION:
Same mechanism of action as sirolimus.
It inhibits activation of T cells by forming a complex with FKBP-12 and subsequently blocking mTOR.
CLINICAL APPLICATION:
Approved for use in renal transplantation.
in combination with basiliximab, cyclosporine, and corticosteroids
It is also indicated for second-line treatment in patients with advanced renal cell carcinoma.
ADVERSE EFFECTS:
Adverse effects similar to sirolimus.
An additional adverse effect
Angioedema
kidney arterial and venous thrombosis.

36. azathiopurine Antimetabolite DESCRIPTION MECHANISM
Prodrug that releases 6-mercaptopurine
Widespread use in organ transplantation
MECHANISM
Purine synthesis inhibitor
Inhibiting the proliferation of cells, especially leukocyte.
Converts 6-mercaptopurine to tissue inhibitor of metalloproteinase, which is converted to thioguanine nucleotides that interfere with DNA synthesis; thioguanine derivatives may inhibit purine synthesis
Prevents mitosis and proliferation of rapidly dividing cells, such as activated B and T lymphocytes

37. Azathioprine is metabolized to 6-mercaptopurine (6-MP), which is either inactivated by two enzymes, thiopurine s-methyltransferase (TPMT) and xanthine oxidase (XO), or is further metabolized to thioinosine monophosphate (TIMP).

38. azathiopurine Prescribed for Side effect FDA : Non-FDA :
Renal transplantation
Rheumatoid Arthritis
Non-FDA :
Multiple Sclerosis (disease involving damage to the sheaths of nerve cells in the brain and spinal cord),
Crohn's disease (a chronic inflammatory disease of the intestines, especially the colon and ileum)
Myasthenia gravis, chronic ulcerative colitis, and autoimmune hepatitis
Side effect
Leukopenia, bone marrow depression, liver toxicity (uncommon); blood-count monitoring required

39. CYCLOPHOSPHOMIDE More marked effect on B cells and humoral immunity.
Used in BM transplantation in which short course with high dose is given.
In other organ transplantations it is employed only as a reserve drug.
In RA, it is rarely used.
Low doses are occasionally employed for maintenance therapy in SLE (autoimmune disease affect the skin, joints, kidneys, brain, and other organs.) and thrombocytopenic purpura.

40. METHOTREXATE Folate antagonist
Markedly depresses cytokine production and cellular immunity and has anti-inflammatory property
Used as 1st line drug in many autoimmune diseases like rapidly progressing RA, severe psoriasis (a skin disease marked by red, itchy, scaly patches), myasthenia gravis, uveitis, chronic active hepatitis
Low dose as maintenance therapy is relatively well tolerated.

41. MYCOPHENOLATE MOFETIL
MECHANISM:-
As an ester, it is rapidly hydrolyzed in the GI tract to mycophenolic acid.
Mycophenolic acid is quickly and almost completely absorbed after oral administration.
This is a potent, reversible, noncompetitive inhibitor of inosine monophosphate dehydrogenase, which blocks the de novo formation of guanosine phosphate.
Thus,like 6-MP, it deprives the rapidly proliferating T and B cells of a key component of nucleic acids.
ADR:
Most common adverse effects:
GI, including diarrhea, nausea, vomiting, and abdominal pain.
High doses of mycophenolate mofetil
Associated with a higher risk of CMV infection.
CLINICAL APPLICATION:-
Replaced azathioprine because of its safety and effcacy in prolonging graft survival.
It has been successfully used in heart, kidney, and liver transplants.

43. GLUCOCORTICOIDS Potent immunosuppressant and antiinflammatory
MECHANISM:
Inhibits several components of the immune response
They particularly (-) MHC expression and proliferation of T lymphocytes.
Expression of several IL and other cytokine genes is regulated by corticosteroids.
The short lived rapid lymphopenic effect of steroids is due to sequestration of lymphocytes in tissues.

44. Inhibition of gene expression
Glucocorticoids
Steroid hormones, have broad anti inflammatory activity.
Binds with glucocorticoid receptor.
glucocorticoid - glucocorticoid receptor complex translocate to nucleus.
Binds to GREs in specific genes
Regulates the gene expression
down regulate the inflammatory mediators.
(IL1, IL4 TNFα etc.)
( glucocorticoid response elements)

46. USES - GLUCOCORTICOIDS
Transplant rejection
BM transplantation
Autoimmune diseases – RA, SLE, Hematological conditions
Psoriasis
Inflammatory Bowel Disease, Eye conditions
GVH: graft verses host

47. TOXICITY Growth retardation Avascular Necrosis of Bone
Risk of Infection
Poor wound healing
Cataract
Hyperglycemia
Hypertension

48. IL-2 RECEPTOR ANTIBODIES
BASILIXIMAB
MECHANISM:-
Chimeric murine monoclonal antibody against human IL-2 receptor alpha subunit of activated T to block T cell
Blocks activation and inhibits clonal expansion of T cells
Blockade of this receptor foils the ability of any antigenic stimulus to activate the T-cell response system.
GI toxicity as the main adverse effect.
USE:
Used to induce immunosuppression and to prolong organ transplants in combination with immunosuppressants.

49. DACLIZUMAB DESCRIPTION MECHANISM
Humanized monoclonal antibody against CD25 (interleukin-2– receptor α chain)
MECHANISM
Binds to and blocks the interleukin-2– receptor α chain (CD25 antigen) binds with high-affinity to the Tac subunit of the high-affinity IL-2 receptor complex and inhibits IL-2 binding
on activated T cells, depleting them and inhibiting interleukin-2–induced T-cell activation

50. DACLIZUMAB PRESCRIBED FOR SIDE EFFECT Renal, cardiac transplant
Hypersensitivity reactions (uncommon)
Gastrointestinal disorders
Does not appear to increase the incidence of opportunistic infections or malignancies

51. CYTOKINE INHIBITORS
TNF inhibitors (disease modifiers to treat rheumatoid arthritis)
Etanercept
Recombinant version of TNF receptor
Infliximab
Chimeric human/murine anti-TNF monoclonal antibody
Anakinra
Human IL-1 receptor antagonist
Disease modifier agent for Rheumatoid arthritis

53. MUROMONAB-CD3 Description Mechanism
Murine monoclonal antibody against CD3 component of T-cell–receptor signal-transduction complex
Mechanism
Monoclonal IgG2a antibody
Binds to the T cell receptor-CD3-complex on the surface of circulating T cells, interfering with the receptor-antigen-interaction
Resulting in a transient activation of T cells, release of cytokines, and blocking of T-cell proliferation and differentiation
T-cell function usually returns to normal within approximately 48 hours of discontinuation of therapy.

55. MUROMONAB-CD3 PRESCRIBED FOR SIDE EFFECT
Renal, heart and liver transplant
SIDE EFFECT
Severe cytokine-release syndrome, pulmonary edema, acute renal failure, gastrointestinal disturbances, changes in central nervous system
Pyrexia(fever),myalgia, nausea and diarrhoea

56. ALEMTUZUMAB DESCRIPTION MECHANISM
Humanized monoclonal antibody against CD52, a 25-to-29-kD membrane protein
MECHANISM
Binds to CD52 on all B and T cells, most monocytes, macrophages, and natural killer cells, causing cell lysis and prolonged depletion

57. ALEMTUZUMAB PRESCRIBED FOR SIDE EFFECT CLL and T cell lymphoma
Hypotension, fever, shortness of breath, bronchospasm, chills, and/or rash

58. POLYCLONAL ANTIBODY
Antithymocyte globulin-equine (Atgam®), Antithymocyte globulin-rabbit (RATG, Thymoglobulin®)
Description
Polyclonal antibodies are directed against lymphocyte antigens, directed against multiple epitopes

59. POLYCLONAL ANTIBODY MECHANISM
Agents contain antibodies specific for many common T cell antigens including CD2, CD3, CD4, CD8, CD11a, CD18
Effectively depletes T-cell concentration in the body through complement-dependent cytolysis and cell mediated opsonization
Following with T cell clearance from the circulation by the reticuloendothelial system

60. POLYCLONAL ANTIBODY SIDE EFFECT Leukopenia
serum sickness (cross-reactivity with other tissue antigens)
adversely affects the ability of the patient to make antibodies against foreign protein
thrombocytopenia
pruritis
fever
arthralgias
opportunistic infections
malignancies

61. ANTI –D IMMUNEGLOBULIN
Human Ig G having high titre of antibodies against Rh (D) antigen
It binds the Rho Ag (-) antibody formation in Rh -ve individuals
It is used for prevention of postpartum /post –abortion formation of antibodies in Rho-D negative.
Administered within 72 hrs of delivery /abortion, such treatment prevents Rh hemolytic disease in future offspring.
It has also been given at 28th week of pregnancy
Never be given to Rh +ve individuals

64. THANK YOU -PHARMA WORLD