Chapter 18: Blood Group Typing and Protein Profiling

Blood groups

Blood groups

Defined as antigen polymorphisms present on erythrocyte surfaces.

Transfusion reactions

These occur when an incompatible type of blood is transfused into an individual, which can lead to severe symptoms or even death.

Karl Landsteiner

He discovered the first blood group, known as the ABO system, in the early 1900s, while studying transfusion and transplantation.

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The International Society of Blood Transfusion currently recognizes ____ blood group systems, which include hundreds of antigen polymorphisms

Type A

_____ individuals have the A antigen.

Type B

___ individuals have the B antigen.

Type AB

____ individuals have both A and B antigens.

Type O

____ individuals have neither A nor B antigens.

The O antigen is synthesized by _______, a fucose transferase encoded by the FUT genes, which adds a fucose on the end of a glycolipid or glycoprotein.

A allele

____ produces the A-transferase, which transfers N-acetylgalactosamine to the O antigen and thus synthesizes the A antigen

B allele

_____ produces the B-transferase, which transfers galactose to the O antigen and thus synthesizes the B antigen.

O allele

_____ has a mutation (small deletion), which eliminates transferase activity, and no modification of the O antigen occurs.

secretors

Individuals whose A, B, and O antigens can be found in other types of bodily fluids are referred to as ______.

FUT1

It is expressed in tissues of mesodermal origin and is responsible for the synthesis of the O antigen in erythrocytes.

FUT2

It is expressed in tissues of endodermal origin; it is responsible for the synthesis of the O antigen in secretions.

Lattes Crust Assay

It relies on the principles of Landsteiner’s experiments. It is an agglutination-based assay that utilizes the A, B, and O indicator cells to test the agglutination reaction with its corresponding naturally occurring serum antibodies in a questioned sample.

Absorption–Elution Assay

It is highly sensitive and can be used for testing dried bloodstains. This method indirectly detects the presence of antigens.

Native electrophoresis

______ can be used to isolate proteins for studying the functions of proteins.

Reducing Agents

It is common to include reducing agents such as mercaptoethanol (ME), dithiothreitol (DTT), or sodium mercaptoethane sulfonate (MESNA) to denature proteins.

Sodium dodecylsulfate (SDS)

A strong anion detergent that binds to most proteins in amounts proportional to the molecular weight of the protein.

Separation by Isoelectric Point

It can be used to separate proteins according to their isoelectric points (pI).

Isoelectric Points

It is the pH value at which the net electric charge of an amino acid is zero.

pH gradient

In IEF electrophoresis, a ____ is created in a gel between the electrodes, and a protein sample is placed in a well on the gel.

pH gradient

A _____ in the gel is established by utilizing materials such as carrier ampholytes or immobilines that are dispersed in the gel.

Carrier ampholytes

These are synthetic amphoteric compounds that contain multiple weak ionizable moieties acting as either acids or bases.

Isoenzymes

Are multiple forms of an enzyme that catalyze the same reaction but differ in their amino acid sequences.

Phosphoglucomutase (PGM)

An important metabolic enzyme, catalyzes the reversible conversion of glucose-1-phosphate and glucose-6-phosphate.

Fetal Hemoglobin

The dominant form of hemoglobin present in the fetus during gestation.

Hemoglobin S

An inherited variant of normal adult hemoglobin

Haptoglobin (Hp)

The most widely used of the polymorphic serum proteins in forensic biology. It is a protein that binds and transports Hb from the bloodstream to the liver for the recycling of the iron contained in the Hb.