Antimicrobial peptides from human platelets.

Tang YQ, Yeaman MR, Selsted ME

Infection and immunity1 Dec 2002Cited by 402 (Europe PMC)

PMID12438321PMCIDPMC132966DOI10.1128/iai.70.12.6524-6533.2002PepBankPUB-12438321

Summary

The text of this summary is not shown here, because the article license does not allow reuse. Read it at the source (opens in a new tab)

Text rights: Publisher copyright. Results still quote short attributed sentences.

Results from this study5

2 results from studies that gave the peptide. No result from this study comes from people.

01LabIn vitro (cells)Activity measurement
In vitro, platelet-derived thymosin beta‑4 was active against at least two of the four tested bacterial and fungal organisms.
In plain wordsIn lab tests, thymosin beta‑4 from platelets was active against at least two of the four microbes tested.
Peptide
Thymosin beta-4 (human)
Outcome
Not applicableAntimicrobial activity against bacteria and fungi
Study
E. coli, S. aureus, C. albicans, C. neoformansn: not reported in source
in vitro antimicrobial assays
Outcome group
Infection and antimicrobial activity · Infection
Studied dose
Dose not stated
Source sentences
Summary
Each peptide exerted activity against at least two organisms.
1 context sentence(design, population, supporting numbers)
Summary · context
The in vitro antimicrobial activities of the seven released peptides were further tested against bacteria (E. coli and Staphylococcus aureus) and fungi (Candida albicans and Cryptococcus neoformans).
Report a problemFND-1243832103
02LabIn vitro (cells)Activity measurement
In vitro, thymosin beta‑4 had greater antimicrobial activity at alkaline pH, whereas activity was generally greater at acidic pH for the seven platelet peptides.
In plain wordsIn lab tests, thymosin beta‑4 killed microbes better at alkaline pH, while most other platelet peptides worked better at acidic pH.
Peptide
Thymosin beta-4 (human)
Outcome
Not applicablepH dependence of antimicrobial activity
Study
E. coli, S. aureus, C. albicans, C. neoformansn: not reported in source
in vitro antimicrobial assays
Outcome group
Infection and antimicrobial activity · Infection
Studied dose
Dose not stated
Source sentences
Summary
Exceptions to these observations were observed with PF-4, which displayed a bimodal dose-response relationship in microbicidal assays, and Tbeta-4, which had greater activity at alkaline pHs.
2 context sentences(design, population, supporting numbers)
Summary · context
Generally, the peptides were more potent against bacteria than fungi, activity was greater at acidic pHs, and antimicrobial activities were dose dependent.
Summary · context
The in vitro antimicrobial activities of the seven released peptides were further tested against bacteria (E. coli and Staphylococcus aureus) and fungi (Candida albicans and Cryptococcus neoformans).
Report a problemFND-1243832104

Natural levels measured2

These results measure the body's own peptide. Nobody was given the peptide. They are not evidence about taking it. They are left out of key results, evidence counts and charts.

03LabEndogenous levelEx vivo tissueOther
Thymosin beta‑4 was identified among seven antimicrobial peptides released from human platelets after thrombin stimulation.
In plain wordsIn lab tests, human platelets released their own thymosin beta‑4, one of seven peptides with antimicrobial activity, after thrombin stimulation.
Peptide
Thymosin beta-4 (human)
Outcome
Not applicableRelease of thymosin beta-4 from thrombin-stimulated platelets
Study
humann: not reported in source
human platelets stimulated with thrombin
Outcome group
Infection and antimicrobial activity · Immune and inflammation
Source sentences
Summary
These analyses enabled the identification of seven thrombin-releasable antimicrobial peptides from human platelets: platelet factor 4 (PF-4), RANTES, connective tissue activating peptide 3 (CTAP-3), platelet basic protein, thymosin beta-4 (Tbeta-4), fibrinopeptide B (FP-B), and fibrinopeptide A (FP-A).
1 context sentence(design, population, supporting numbers)
Summary · context
To evaluate the potential antimicrobial activities of platelet proteins, normal human platelets were stimulated with human thrombin in vitro.
This result measures the body's own Thymosin beta-4 (human). Nobody was given the peptide. It is not evidence about taking it.
Report a problemFND-1243832101
04LabEndogenous levelEx vivo tissueOther
Thymosin beta‑4 was also purified from acid extracts of nonstimulated human platelets.
In plain wordsIn lab tests, the body's own thymosin beta‑4 was also found in extracts of human platelets that were not stimulated.
Peptide
Thymosin beta-4 (human)
Outcome
Not applicableThymosin beta-4 in nonstimulated platelets
Study
humann: not reported in source
acid extracts of nonstimulated human platelets
Outcome group
Infection and antimicrobial activity · Immune and inflammation
Source sentences
Summary
With the exception of FP-A and FP-B, all peptides were also purified from acid extracts of nonstimulated platelets.
This result measures the body's own Thymosin beta-4 (human). Nobody was given the peptide. It is not evidence about taking it.
Report a problemFND-1243832102

Studies that did not test the peptide alone1

In this study, Thymosin beta-4 (human) was a lab tool or a carrier, part of a mix, or the subject of a lab method. These results are not evidence about taking Thymosin beta-4 (human).

05LabNot a test of Thymosin beta-4 (human) aloneIn vitro (cells)Activity measurement
In vitro, the seven platelet peptides taken together were generally more potent against bacteria than fungi, and their antimicrobial activities were dose dependent.
In plain wordsIn lab tests, the seven platelet peptides as a group worked better against bacteria than fungi, and their effects grew with dose.
Peptide
Thymosin beta-4 (human)
Outcome
Not applicablePotency and dose dependence of seven platelet peptides
Study
E. coli, S. aureus, C. albicans, C. neoformansn: not reported in source
in vitro antimicrobial assays
Outcome group
Infection and antimicrobial activity · Infection
Source sentences
Summary
Generally, the peptides were more potent against bacteria than fungi, activity was greater at acidic pHs, and antimicrobial activities were dose dependent.
1 context sentence(design, population, supporting numbers)
Summary · context
The in vitro antimicrobial activities of the seven released peptides were further tested against bacteria (E. coli and Staphylococcus aureus) and fungi (Candida albicans and Cryptococcus neoformans).
In this study, Thymosin beta-4 (human) was a lab tool or a carrier, part of a mix, or the subject of a lab method. This result is not evidence about taking Thymosin beta-4 (human).
Report a problemFND-1243832105

AI wrote and checked these results. AI can make mistakes, so check important results against the source.

Version history

PepBank keeps every version of the data on this study. Status changes from Retraction Watch, Europe PMC and Crossref are listed with their source.

Version 2Current
13 Oct 2026, 01:52 UTC
Study results updated
Version 1
12 Oct 2026, 18:17 UTC
First added · source update from Europe PMC

Subjects

Terms as the source lists them.

Publication types

MeSH terms

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