Lectins are carbohydrate-binding proteins or glyco-proteins binding selectively without the involvement of enzymes, Gene responsible for expression lection found in chromosome 10q11.2-q21 Found in plnats grains, legume, soy bean, kidney bean Lectins recognize tumor marker which play important role for diagnosing tumor cell, screening tumour and able to detect subtle neoplastic changes

2. What is the Gene Therapy?
 It is a technique for correcting defective genes that are
responsible for disease development, it mean using genes to
treat or prevent disease
• There are three approaches:
1. Replacing a mutated gene that causes disease with a healthy
copy of the gene.
2. Inactivating, or “knocking out,” a mutated gene that is
functioning improperly.
3. Introducing a new gene into the body to help fight a disease.

3. In the future, this
technique may allow
doctors to treat a
disorder by inserting a
gene into a patient’s
cells instead of using
drugs or surgery,
Gene Therapy

4. 1. Scientists focused on diseases caused by single-gene defects, such as
* cystic fibrosis
* haemophilia
* thalassemia
* sickle cell anemia
2. Treatment other diseases
• inherited disorders
• some types of cancer
• viral infections
Which diseases can be treated?

5. • The first gene therapy was performed on
September 14th, 1990
– Ashanti DeSilva was treated for SCID
• Sever combined immunodeficiency
– Doctors removed her white blood cells,
inserted the missing gene into the WBC, and
then put them back into her blood stream.
– This strengthened her immune system
– Only worked for a few months 
The First Case

6. • Gene transplantation
(to patient with gene deletion)
• Gene correction
(To revert specific mutation in the gene of interest)
• Gene augmentation
(to enhance expression of gene of interest)
Gene therapy could be
very different for different diseases

7. the therapeutic genes are transferred into the somatic cells of a
patient. Any modifications will be restricted to the individual patient
only, and will not be inherited to offspring.
Several experiments are currently in clinical
trials with varied success. Over 600 clinical trials
utilizing somatic cell therapy are underway in
the United States
Somatic gene therapy

8. Germ cells (sperm or eggs) are modified by the introduction of functional
genes, which are integrated into their genomes. if a germ cell is genetically
modified then all the cells in the organism will contain the modified gene.
This would allow the therapy to be heritable and passed on to later
generations. Although this should be highly effective in counteracting
genetic disorders and hereditary diseases, some country prohibit this
application in human beings, at least for the present, for technical and
ethical reasons, including insufficient knowledge about possible risks to
future generations and higher risk than somatic gene therapy,
Germline gene therapy

9. Types of gene therapy

11. In these process bacterial DNA is moved from one
bacterium to another by a virus (a bacteriophage).
Methods of gene therapy

13. Methods of gene therapy
This process is relatively common in
bacteria, but less so
in eukaryotes. Transformation is often
used in laboratories to insert novel
genes into bacteria for experiments or
for industrial or medical applications.

14. Methods of gene therapy

16. Vector

17. All viruses bind to their hosts and introduce their genetic material into
the host cell as part of their replication cycle, First removing the viral
DNA that cause disease replace those genes with genes encoding
the desired effect and using the virus as a vehicle to deliver the
therapeutic DNA. This genetic material contains basic 'instructions' of
how to produce more copies of these viruses,the host cell will carry
out these instructions and produce additional copies of the virus,
leading to more and more cells becoming infected.
A number of viruses have been used for human gene therapy,
including
retrovirus
adenovirus
lentivirus
herpes simplex virus
pox virus
adeno-associated virus.
Viral vectors

20. Viral vectors

21. P53 tumor suppressor gene
• When in mutates, p53 can lose its
suppressive powers which effects of
abnormal cell growth
• P53 is the most commonly mutated
gene found in human tumors

22. Direct injection to tumor

23. The adenovirus
containing the p53 gene
binds to the receptor in
the cell membrane of the
cancer cell
Mechanisms

24. Mechanisms
The adenovirus
injects its gene,
which now
includes the p53
tumor
suppressor
gene. In to the
cell nucleus

25. P53 expressed to
produce protein
damage DNA and
cell suicide
(apoptosis)
Mechanisms

26. •Over 16,000 patients alteady treated
•No serious side effects
•Common side effects is self limited fever
P53 gene therapy is safe?

27. 1. Viruses can usually infect more than one type of cell. when
viral vectors are used to carry genes into the body, they might infect
healthy cells as well as cancer cells
2. the new gene might be inserted in the wrong location in the DNA,
possibly causing harmful mutations to the DNA .
3. there is a slight chance that this DNA could be introduced into the
patient’s reproductive cells. If this happens, it could produce changes
that may be passed to offspring
4. transferred genes could be overexpressed, producing so much of the
missing protein as to be harmful.
5. the viral vector could cause an immune reaction;
6. and that the virus could be transmitted from the patient to other
individuals or into the environment.

28. Disease Defect Target cell
immunodeficiency Bone marrow cells
T-lymphocytes
Hemophilia Liver, muscle
Cystic fibrosis Lung Cells
Cancer Many cell types
Neurological diseases Parkinson’s/
Alzheimers
Nerve Cells
Infectious diseases AIDS, hepatitis B White Blood Cells

29. • Spontaneous uptake by endocytosis
• Plasmid liposome complex
• Uncovered plasmids
• Gene gun methods
• electroporation

30. Is a technique in which an electrical field is applied to cells in
order to increase the permeability of the cell membrane,
allowing DNA to be introduced into the cell
Electroporation

32. Introducing Chromosome

33. To improve and facilitated the delivery of the new DNA into the cell, the DNA must be
protected from damage. DNA can be covered with lipids like a liposome, is complex
DNA with liposome is called lipoplex
The most common use of lipoplexes has been in gene transfer into cancer cells, where
activated tumor suppressor genes in the cell and decrease the activity of oncogenes

34. Called naked DNA or vector DNA, it is histone
free DNA that is passed from cell to cell during a gene
transfer
Direct injection of free DNA into certain tissues,
particularly muscle, the simplicity of this technique has
led to its adoption in a number of clinical protocols,
this technique has been applied to the gene therapy of
cancer where the DNA can be injected directly into the
tumour

35. DNA plasmid vector vaccines carry the genetic
information encoding an antigen, allowing the
antigen to be produced inside of a host cell,
leading to a cell-mediated immune response
via the MHC I pathway. The plasmid DNA
vaccine carries the genetic code for a piece of
pathogen or tumor antigen. The plasmid
vector is taken up into cells and transcribed in
the nucleus
DNA vaccines or plasmid vector

36. 1. amplifying bacterial plasmid, The bacterial
plasmids inserts using recombinant DNA
technology, where bacterial growth produces
multiple plasmid copies. The plasmid DNA is then
purified from the bacteria, by separating the
circular plasmid from bacterial DNA and other
bacterial impurities. This purifies DNA acts as the
vaccine
2.delivery of plasmids through intramuscular,
intradermal and intravenous injection. The skin
and mucous membranes are the best site for
immunization due to the high concentrations of
dendritic cells (DC), macrophages and
lymphocytes . Intradermal injection of DNA with a
gene gun have been used.
Mechanisms

37. 1. The single stranded mRNA
2. is translated into protein in the
cytoplasm. The DNA vaccine-derived
protein antigen
3. is then degraded by proteases into
intracellular peptides
4. The vaccine derived-peptide binds
MHC class I molecules
5. Peptide antigen/MHC I complexes are
presented on the cell surface
6. binding cytotoxic CD 8+ lymphocytes,
and inducing a cell-mediated immune
response., . CTLs inhibit viruses
through both cytolysis or by cytokine
production
( chemokines, interferons,interleukins,
lymphokines, tumour necrosis factor)
Mechanisms

38. • The foreign protein can also be presented by the MHC class II pathway by APCs
which elicit helper T cells (CD4+) responses. These CD4+ cells are able to recognize
the peptides formed from exogenous proteins that were endocytosed or
phagocytosed by APC, then degraded to peptide fragments and loaded onto MHC
class II molecules. Depending on the the type of CD4+ cell that binds to the
complex, B cells are stimulated and antibody production is stimulated. This is the
same manner in which traditional vaccines work

39. • induce the expression of antigens that resemble native viral epitopes more
closely than standard vaccines do since live weakened or killed vaccines are
often altered in their protein structure and antigenicity.
• Plasmid vectors can be constructed and produced quickly and the coding
sequence can be manipulated in many ways, costs lower than traditional
vaccines.
• DNA vaccines encoding several antigens or proteins can be delivered to the
host in a single dose.
• they are also very temperature stable making storage and transport much
easier.
• The continues expression of the viral antigen caused by gene vaccination in
an environment containing many APCs (antigen processing cell) may
promote successful therapeutic immune response which cannot be
obtained by other traditional vaccines .
Advantages

40. Although DNA can be used to raise immune responses against pathogenic proteins,
certain microbes have outer capsids that are made up of polysaccharides. This
limits the extent of the usage of DNA vaccines because they cannot substitute for
polysaccharide-based subunit vaccines .
Limitations

42. • Short Lived
– Hard to rapidly integrate therapeutic DNA into genome and rapidly
dividing nature of cells prevent gene therapy from long time
– Would have to have multiple rounds of therapy
• Immune Response
– new things introduced leads to immune response
– increased response when a repeat offender enters
• Viral Vectors
– patient could have toxic, immune, inflammatory response
– also may cause disease once inside
• Multigene Disorders
– Heart disease, high blood pressure, Alzheimer’s, arthritis and diabetes
are hard to treat because you need to introduce more than one gene
• induce a tumor if integrated in a tumor suppressor gene because
insertional mutagenesis
Problems with Gene Therapy

43. Lectins in gene therapy

44. Lectins are carbohydrate-binding proteins or glyco-
proteins binding selectively without the involvement of
enzymes specific for carbohydrate ligands. Lectins are
present in organisms and play very important roles in life,
Lectins' functioning mechanism is based on the reaction of
glycolysation
Gene responsible for expression
lection found in chromosome 10q11.2-
q21
Found in plnats grains, legume, soy
bean, kidney bean

45. • Recognition of cells, carbohydrates, and proteins
• Bind soluble extracellular and intercellular glycoproteins.
• The regulation of cell adhesion
• Cell differentiation
• lectins are found on the surface of liver cells that specifically
recognize galactose residues. It is believed that these cell-
surface receptors are responsible for the removal of certain
glycoproteins from the circulatory system.
• Control of protein levels in the blood.

46. Lectins recognize tumor marker which play important
role for diagnosing tumor cell, screening tumour and
able to detect subtle neoplastic changes
Tumour marker are molecules that can be detected in
blood fluids or tissue, which are produced as a
response to cancer or by caner cells themselves

47. mannose-bindig lectins are interacting with
the carbohydrate chains Lectin has
glycoconjugates property which bind to
different carbohydrate, lectins bind to cell
membrane carbohydrate (antigen), tumor cell
has altered antigen with the use of lectin affinity
chromatography (LAC) and histochemistry
methods by comparing tumor antigen with
normal cell antigen, lectins provide practical
application during observation of changes
occurring in the cell membrane in different
stages of physiological and pathological
development of human cell, and tumour
diagnosis and scanning

48. Lectin suppress cancer cell growth and
metastasis by blocking polyamines
• Polyamines growth factor are synthesized in the body or
derived form the diet, or produce by bacteria in the gut, or
by cancer cell they are essential to cellular proliferation and
differentiation
• Lectin cause (polyamine deprivation) by decreasing
digestion of polyamines then cell growth is stopped

49. • Cancer cell produce polyamines, which adsorbed by lymphocyte lead to
1. inhibit anti-tumor cells called natural Killer cells
2. metastasis (tumor cell spread) when polyamines level increase
immune cells fail to recognize cancer cell antigen and decreased cytotoxic
activity of killer cell

50. Mannose-binding lectin (MBL), is a lectin that is induce innate immunity, a low
expression of an MBL1 was detected in liver.
• mutations in exon 1 of the human MBL2 gene at codon 52 reduce the level of
functional serum MBL by disrupting the collagenous structure of the protein.
• nucleotide substitutions in the promoter region of the MBL2 gene affect the MBL
serum concentration
MBL belongs to the class of collectins in the C-type lectin, whose function is
carbohydrate antigen recognition of bacteria, viruses, and fungi. MBL in the first
line of defense results in activation of the lectin pathway of the complement
system.
The polymorphisms of exon 1 cause susceptibility to various common infections,
including meningococcal disease.

52. lectins inducing apoptosis , lectin found in the seeds of the castor plant.
Has cytotoxic effect that kill human cell , a lethal dose of purified ricin is
approximately 1 milligram per kilogram of body weight.
• Lectin toxicity is by inhibiting protein synthesis
1. with immuno-modulatory or antiproliferative activity lectin belonging to
II-RIP class (Ribosome Inactivating Proteins)
2. prevent assembling amino acids to proteins during translation of mRNA or
by cause cell death (a ppotosis) this cell-killing activity of lectin make it
useful for treatment of tumor cell.
1. Cancer treatment by castor Lectins

53. Lectins found in Mistletoe plant induce apoptosis by
1. inhibition of telomerase activity
2. promote of p53- and p21 independent pathway
(suppresser gene)
Telomerase Is the enzyme that add
repeats DNA sequence to
the 3' end of DNA strands that
promote chromosomal stability,
Telomere shortness in human is a
marker of disease and cancer.
2. Cancer treatment by Mistletoe Lectins

54. Plant Lectin PHA (phytohaemagglutinin) found in legume has
carbohydrate-binding specificity for a complex oligosaccharide
containing galactose, and mannose, possess anticancer properties in vitro,
in vivo, bind to cancer cell membranes or their receptors, causing
cytotoxicity, apoptosis, and inhibition of tumor growth.
• Has mitogenic effect in lymphocyte which trigger lymphocyte differentiate
and produce T cell and which increase immune response to tumour
3. Cancer treatment by legume Lectins

55. 1. Lectins mediate attachment and binding of bacteria and viruses
2. Plant Lectin PHA (phytohaemagglutinin) has mitogenic effect in lymphocyte
which trigger lymphocyte differentiate and produce T cell.
3. lectin is a receptor that recognizes hydrolytic enzymes containing mannose-6-
phosphate, and targets these proteins for delivery to the lysosomes.
4. Lectins play important roles in the immune system by recognizing carbohydrates
that are found on pathogens, Examples are the lectin complement activation
pathway and mannose-binding lectin.
5. A lectin (BanLec) from bananas inhibits HIV-1 in vitro
6. They also affect the immune system by altering the production of interleukins, or
activating protein kinases

56. • Lectins may be disabled by specific charbohydrate which bind to ingested
lectins from grains, legume plants and dairy; binding can prevent their
attachment to the carbohydrates within the cell membrane. Cause
intestinal irritation
• Some lectins may be powerful toxins , have been incorporated
into genetically engineered crops to transfer traits, such as resistance to
pests and resistance to herbicides.