Is there a type of blood cell that can reach all other body cells? By "reach", I mean to "touch" the surface of the target cell.

If we look at the red blood cell for example, that moves in blood vessels, there are cells close by - after the wall of blood vessel - that get oxygen by diffusion and not by direct contact, as far as I know.

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    $\begingroup$ Drugs are usually not recognized by the immune system. Can you explain further, why you want to do this? And which disease you want to target? $\endgroup$
    – Chris
    Dec 29, 2014 at 12:12
  • $\begingroup$ Usually but there are some that may lead to immune response: en.wikipedia.org/wiki/Idiosyncratic_drug_reaction Also it is a way to improve targeting, theoretically. I added a link in the question about using of Red blood cells. My question more about the type of cells that can reach all the cells and organs in a body. Thank you. $\endgroup$
    – Robertos
    Dec 29, 2014 at 12:49
  • $\begingroup$ That's why I was asking what disease you want to target. You not only have to get the drug inside you transporter cell, you have also get it out again on the right place (and presumably only there). $\endgroup$
    – Chris
    Dec 29, 2014 at 13:05
  • $\begingroup$ You right, Chris, it's very theoretical. There are no some special disease. I was thinking about using cell like "inside doctor". The cell will recognize the target and make some action. So need to chose some cell to start from it. This cell need to reach all the cells in the body and about that is my question. How to teach the cell to do it, is much much complicated =) Just wondering if there is cell that reach all the places in the body (or most of them). $\endgroup$
    – Robertos
    Dec 29, 2014 at 13:34
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    $\begingroup$ Why not use a PEGylated liposome or something to coat the drugs in a protective layer? You could add a targeting ligand to the surface to help direct it toward receptors at the target site and not need to rely on getting into and out of transport cells. Also, there is quite a bit of existing research to build on. $\endgroup$
    – user137
    Dec 29, 2014 at 17:35

1 Answer 1


No, there is not. Cells in the bloodstream reach most areas in the body, but there are certain privileged areas which stop cells, drugs and macromolecules from leaving the bloodstream and entering the tissue. These privileged areas are thought to exist in sensitive or important areas for their own protection:

Immune privilege is thought to be an evolutionary adaptation to protect vital structures from the potentially damaging effects of an inflammatory immune response. (Wikipedia)

The most common example of such an area is the blood-brain barrier, but there other barriers to privileged areas, including the blood–testis barrier, the blood-retinal barrier and the blood-ocular barrier. Cells do not pass from the blood through these barriers, except in disease (Larochelle et al. 2011).

Related reading:

The first chapter of Blood Groups and Red Cell Antigens has a decent high-level overview of different types of blood cells and their roles in the bloodstream and the immune system.

How do immune cells overcome the blood–brain barrier in multiple sclerosis? Larochelle et al. 2011

  • $\begingroup$ Thank you! But in wiki - "Antigens from immune privileged regions have been found to interact with T cells in an unusual way" - that mean that T cells reach the region, just don't work. $\endgroup$
    – Robertos
    Jan 6, 2015 at 20:52
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    $\begingroup$ That actually means that antigens that escape from the privileged regions (usually due to injury or illness) are recognized by the immune system in ways we don't understand. This interaction is not a normal occurrence. Reading further, you can see that there are immune cells in some of those areas (i.e. eye), they just don't move back and forth $\endgroup$
    – Luigi
    Jan 6, 2015 at 20:56

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