Encapsulation of implanted foreign bodies by hemocytes in Locusta migratoria and Melolontha melolontha

Area of Science:

• * Insect immunology and cellular responses to foreign bodies.
• * Comparative study of invertebrate immune mechanisms.

Background:

• * Understanding how invertebrates respond to implanted foreign materials is crucial for invertebrate immunology.
• * Hemocytes are key cellular components of the invertebrate immune system.

Purpose of the Study:

• * To investigate the immediate cellular response of insect hemocytes to implanted sterile foreign materials.
• * To characterize the ultrastructural changes in hemocytes forming capsules around foreign bodies.

Main Methods:

• * Sterile fragments of cellophane, cat-gut, cotton, and beef muscle were implanted into the body cavity of Locusta migratoria and Melolontha melolontha.
• * The encapsulated foreign bodies and surrounding hemocytes were examined using microscopy to observe cellular responses and material degradation.

Main Results:

• * Implanted foreign materials were immediately surrounded by granular hemocytes, forming multi-layered capsules.
• * The cytoplasm of outer-zone granular hemocytes showed accumulation of fibrous material, including microtubules and microfilaments.
• * No evidence of degradation of the implanted materials was observed.

Conclusions:

• * Insects utilize granular hemocytes to encapsulate foreign bodies, forming a protective barrier.
• * The observed accumulation of fibrous material suggests active cellular processes within the hemocytes during encapsulation.
• * The lack of degradation indicates that encapsulation is the primary immune response, rather than enzymatic breakdown, for these materials.