Problem on clause sentence

Question

I read an article from a newspaper and found a sentence which I feel difficult to comprehen!
Please help!

Extract from the article:
" TD-0680 can block the interaction between HIV and CCR5, a protein on white blood cells to which the virus adheres, preventing it from entering human cells, and thus avoids infection."

Q1) I guess the word in the second sentence : "a protein"
Is it pointing(refering) to CCR5? I think it is a (which, that hidden in this sentence) relative clause. Am I correct?

Q2) about the third sentence, what is the "it" refers to? and what is the type of this sentence(present participle)?

Thanks

Mister Micawber · Accepted Answer

" TD-0680 can block the interaction between HIV and CCR5, a protein in white blood cells to which the virus adheres, preventing it from entering human cells, and thus avoids infection."

Q1) I guess the word in the second sentence : "a protein" Is it pointing(refering) to CCR5? I think it is a (which, that hidden in this sentence) relative clause. Am I correct?-- Yes.

Q2) about the third sentence, what is the "it" refers to? and what is the type of this sentence(present participle)?-- There is no 3rd sentence; it is all one sentence. 'It' in 'preventing it' refers to CCR5. 'Preventing' introduces an adverbial absolute (participial) clause.

Hktrader · Answer

Q1) This sentence refers to CCR5 ("a protein on white blood cells to which the virus adheres") and it is a relative clause(which). But why the relative pronoun "which" is at the middle of the sentence but not the front?

The relative pronoun not usually at the front of the relative clause?
I fall in love with Mary, who has a long golden hair and sweet voice.

Q2) Is the "it" really refers to CCR5? if it is, the original sentence is likely:
preventing CCR5 from entering human cells and thus avoids infection.

but it is wrong to the actual meaning from the article.
CCR5 is something that on white blood protein, and HIV virus usually adheres on CCR5 and causes infection.
so, the reasonable idea should be:
preventing HIV from entering human cells and thus avoids infection/

Is that I make something wrong cause the bias?

BillJ · Answer

TD-0680 can block the interaction between HIV and CCR5, a protein on white blood cells to which the virus adheres, preventing it from entering human cells, and thus avoids infection.

Q1) Yes, it's saying that CCR5 is a protein on which white blood cells ... No, the underlined constituent is not a relative clause (it's not even a clause) - it's a noun phrase functioning as an appositive.

Q2) The salient interpretation of "it" is that it refers to "HIV". The clause preventing it from entering human cells is a present participial clause.

BillJ

Hktrader · Answer

Thank you so much BillJ.
I have the same thought as you.

Refer to Q1) you say that is a noun phrase but not a relative clause.
but why? what is the difference between clause and phrase?

TD-0680 can block the interaction between HIV and CCR5, a protein on white blood cells to which the virus adheres,

Isn't the full sentence is something like:
TD-0680 can block the interaction between HIV and CCR5, which is a protein on white blood cells that the virus adheres,

Terryxpress · Answer

CCR5 is a protein on the surface of white blood cells, not inside the cell. The reporter is correct in his use of the preposition 'on'. As the rest of the sentence makes clear...:
"...to which the virus adheres, preventing it from entering human cells, and thus avoids infection."

BillJ · Answer

hktraderRefer to Q1) you say that is a noun phrase but not a relative clause.but why? what is the difference between clause and phrase?

A clause has a subject and predicate (what's said about the subject), and the head (main) word is a verb. A phrase, on the other hand, has no subject or predicate, and the head word is a noun (in a noun phrase), an adjective (in an adjective phrase), an adverb (in an adverb phrase) and so on.

The constituent a protein on white blood cells to which the virus adheres is a noun phrase whose head word is the noun "protein". Inside that phrase (we say 'embedded') is the underlined relative clause which modifies the noun phrase "a protein on white blood cells" (not CCR5). It's the equivalent of the virus adheres to a protein on white blood cells. Think of it as a clause within a phrase.

hktraderIsn't the full sentence is something like:TD-0680 can block the interaction between HIV and CCR5, which is a protein on white blood cells that the virus adheres,

TD-0680 can block the interaction between HIV and CCR5, a protein on white blood cells to which the virus adheres, preventing it from entering human cells, and thus avoids infection

But that's not what the original said, is it? You're recasting it to make it a relative construction. As originally written, the underlined constituent is a phrase (an appositive phrase to be precise). Relative clauses are identified by the presence of a relative word (who, which etc), and they have a subject and verb. Of course, the meaning is very similar, but we're talking grammar here, not semantics.

The reason it's called an appositive phrase is because it restates (in different words of course) the noun phrase CCR5 and, crucially, either noun phrase could stand alone:

TD-0680 can block the interaction between HIV and CCR5 preventing it from entering human cells, and thus avoids infection.

OR TD-0680 can block the interaction between HIV and a protein on white blood cells to which the virus adheres, preventing it from entering human cells, and thus avoids infection.

In other words, CCR5 = a protein on white blood cells to which the virus adheres.

BillJ

Mister Micawber · Answer

Did I mention that I haven't studied medicine?

CalifJim · Answer

Mister MicawberDid I mention that I haven't studied medicine?

Once we master all the material in this thread, we won't have to.

CJ

Problem on clause sentence

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