Final answer:
The false statement among the options provided is that a subunit vaccine contains live, attenuated organisms. Subunit vaccines actually consist of only part of the pathogen and do not contain any live organisms.
Step-by-step explanation:
Identification of the False Statement
The question involves identifying the false statement among four given choices related to microbiology concepts. After reviewing the provided choices, we can confirm that the statement regarding subunit vaccines is false. Subunit vaccines do not contain live, attenuated organisms; rather, they consist of only a part of the pathogen (such as a protein, sugar, or capsid) that elicits an immune response without the risks associated with using a whole live or attenuated organism.
Gram-negative bacteria are known for possessing endotoxins, specifically in their outer membrane, which can be released when the bacteria die or divide. Syncytium formation does represent a cytocidal effect of a virus, as infected cells fuse to form a multi-nucleated cell. Lastly, A-B toxins are indeed a class of exotoxins that have two components: one for binding to the host cell, and another that disrupts cell function, for example, by inhibiting protein synthesis as seen with the diphtheria toxin.