Effect of chronic microwave radiation on T cell-mediated immunity in the rabbit.

Abstract

Experiments were conducted to elucidate the effects of chronic low power-level microwave radiation on the immunological systems of rabbits. Fourteen male Belgian white rabbits were exposed to microwave radiation at 5 mW/cm2, 2.1 GHz, 3 h daily, 6 days/week for 3 months in two batches of 7 each in specially designed miniature anechoic chambers. Seven rabbits were subjected to sham exposure for identical duration. The microwave energy was provided through S band standard gain horns connected to a 4K3SJ2 Klystron power amplifier. The first batch of animals were assessed for T lymphocyte-mediated cellular immune response mechanisms and the second batch of animals for B lymphocyte-mediated humoral immune response mechanisms. The peripheral blood samples collected monthly during microwave/sham exposure and during follow-up (5/14 days after termination of exposures, in the second batch animals only) were analysed for T lymphocyte numbers and their mitogen responsiveness to ConA and PHA. Significant suppression of T lymphocyte numbers was noted in the microwave group at 2 months (P less than 0.01, delta % 21.5%) and during follow-up (P less than 0.01, delta % 30.2%). The first batch animals were initially sensitised with BCG and challenged with tuberculin (0.03 ml) at the termination of microwave irradiation/sham exposure and the increase in foot pad thickness (delta mm), which is a measure of T cell-mediated immunity (delayed type hypersensitivity response, DTH) was noted in both the groups. The microwave group revealed a better response than the control group (delta % +12.4 vs. +7.54). The animals were sacrificed and the tissue T lymphocyte counts (spleen and lymph node) were analysed.(ABSTRACT TRUNCATED AT 250 WORDS)

AI evidence extraction

Main findings

Fourteen rabbits exposed to 2.1 GHz microwaves (5 mW/cm2) showed significant suppression of peripheral blood T lymphocyte numbers at 2 months and during follow-up compared with sham-exposed rabbits. In a DTH assay, the microwave group showed a larger increase in foot pad thickness than controls.

Outcomes measured

• T lymphocyte numbers (peripheral blood)
• T lymphocyte mitogen responsiveness to ConA and PHA
• Delayed type hypersensitivity (DTH) response (foot pad thickness after BCG sensitization and tuberculin challenge)
• T lymphocyte counts in spleen and lymph node

Limitations

• Abstract truncated; full results (including tissue T lymphocyte counts and B-cell/humoral outcomes) not provided
• SAR not reported; exposure described as power density (mW/cm2)
• Small sample size (two batches of 7 exposed; 7 sham)

{
    "study_type": "animal",
    "exposure": {
        "band": "microwave",
        "source": null,
        "frequency_mhz": 2100,
        "sar_wkg": null,
        "duration": "3 h daily, 6 days/week for 3 months"
    },
    "population": "Male Belgian white rabbits",
    "sample_size": 21,
    "outcomes": [
        "T lymphocyte numbers (peripheral blood)",
        "T lymphocyte mitogen responsiveness to ConA and PHA",
        "Delayed type hypersensitivity (DTH) response (foot pad thickness after BCG sensitization and tuberculin challenge)",
        "T lymphocyte counts in spleen and lymph node"
    ],
    "main_findings": "Fourteen rabbits exposed to 2.1 GHz microwaves (5 mW/cm2) showed significant suppression of peripheral blood T lymphocyte numbers at 2 months and during follow-up compared with sham-exposed rabbits. In a DTH assay, the microwave group showed a larger increase in foot pad thickness than controls.",
    "effect_direction": "mixed",
    "limitations": [
        "Abstract truncated; full results (including tissue T lymphocyte counts and B-cell/humoral outcomes) not provided",
        "SAR not reported; exposure described as power density (mW/cm2)",
        "Small sample size (two batches of 7 exposed; 7 sham)"
    ],
    "evidence_strength": "low",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "microwave radiation",
        "2.1 GHz",
        "rabbit",
        "chronic exposure",
        "T cell-mediated immunity",
        "T lymphocytes",
        "mitogen responsiveness",
        "ConA",
        "PHA",
        "delayed type hypersensitivity",
        "BCG",
        "tuberculin",
        "anechoic chamber",
        "power density 5 mW/cm2"
    ],
    "suggested_hubs": []
}

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