Human Leukocyte Antigen (HLA) typing

[KKAK]

Hi all,
I am a little bit confused about the concept behind Human Leukocyte Antigen (HLA). Part of my project right now requires me to do HLA typing from the blood samples with flow cytometry. Here are my questions.

1. The difference between between HLA class I & II compare to MHC Class I & II. From wiki, HLA genes are part of MHC genes on the same chromosome? I think I am confused about the word "antigen" in HLA.

2. The types of HLA a person can have. In each HLA I or II class, there are many subtypes, like in class I, there is HLA-A1, A2, A3...etc or B7, B8, B13...etc or Cs...etc. My questions is that in a person, do we have one group of each in subclass (A,B,C)? For example, one would have HLA-A2, B7 and Cw01, and also one of each different group in Class II as well?

3. Heterozygous. Can one person be a heterozygote having like HLA-A2/HLA-A1? How would this affect their immunity? Will they recognize MORE antigens with WEAKER response being heterozygous?

4. Suggestions? Currently I am using flow cytometry to screen for HLA-A2 (single color), I can identify people positive or negative for A2, but what would an heterozygote look like if the above is true? Would it look like 2 peaks overlapping each other by half? What would be an cost-effective alternative method for HLA typing?

Thanks a lot, I hope I am clear.

 

[Aaron Barnard]

1. HLA stands for Human Leukocyte Antigen, and MHC stands for Major Histocompatibility Complex. They are similar in that they both refer to the same set of genes located on chromosome 6 of humans. The difference is that the MHC includes more than just the HLA genes, and it is a more general term. The "antigen" in HLA refers to proteins that are encoded by the HLA genes which act as receptors for foreign molecules and can be used by the immune system to identify them.

2. There are two types of HLA: class I (A, B, and C) and class II (DR, DQ, and DP). Each of these classes has many different subtypes, such as HLA-A1, A2, A3, etc. Generally, a person will have two alleles (one from each parent) for each type of HLA gene, meaning they will have two alleles of each subtype. For example, a person might have HLA-A2/HLA-A1, HLA-B7/HLA-B8, and HLA-Cw01/HLA-Cw02.

3. Yes, a person can be heterozygous for HLA, meaning they have two different alleles for the same gene. This can affect their immunity, as having two different alleles can mean

 

[quicknote]

Hi there,

I am happy to help clarify some of your questions about Human Leukocyte Antigen (HLA) typing. HLA is a complex system of genes that play a crucial role in the immune system by helping the body to recognize and respond to foreign substances, such as viruses and bacteria. Here are my responses to your specific questions:

1. HLA and MHC are often used interchangeably, but there is a slight difference between the two. HLA refers specifically to the human version of the MHC genes, which are found on chromosome 6. MHC genes are also found in other animals, but they may differ in structure and function. The word "antigen" in HLA refers to the specific molecules that are recognized by the immune system as foreign. In the case of HLA, these antigens are proteins found on the surface of cells.

2. Yes, individuals can have multiple subtypes within each HLA class. In fact, it is common for an individual to have a unique combination of HLA subtypes. This is because HLA genes are inherited from both parents, so a person can have one subtype from their mother and a different subtype from their father. This diversity in HLA subtypes allows for a wide range of immune responses to different pathogens.

3. Yes, a person can be heterozygous for HLA genes, meaning they have two different subtypes for a particular HLA class. This is common and does not necessarily affect their immunity. In fact, having a diverse range of HLA subtypes can be beneficial for immune responses as it allows for a broader recognition of antigens.

4. Flow cytometry is a widely used and effective method for HLA typing. In the case of a heterozygote, the two peaks may indeed overlap, but the specific pattern may vary depending on the specific HLA subtype and antibodies used. There are other methods for HLA typing, such as polymerase chain reaction (PCR) and sequencing, which may also be cost-effective options depending on your specific needs and resources.

I hope this helps clarify some of your questions about HLA typing. If you have any further questions, please don't hesitate to ask. Best of luck with your project!