I'm not sure there is:

ναccιnє #1: We obtained cells to test this ναccιnє by murder.

ναccιnє #2: We put murdered baby cells into the ναccιnє.

The use of the cells differs, but complicity in murder is integral to both (i.e., "Yes, I know you murdered a baby to test this ναccιnє,  Please give it to me" versus "Yes, I know there are murdered baby parts in this ναccιnє.  Please give it to me").

The moral complicity seems the same to me.

Fr. Copenhagen mentions it also.  In the case where the DNA is in the vaccine, there is an ongoing current sin which cannot be excused by way of remote or material, the abuse and theft of the bodily remains of the child.

Here's another metaphor:

1) I buy a car that was stolen from someone else.
VS.
2) I buy a car that someone repaired with stolen tools.

In case #2, my mere possession of the car is not an ongoing sin of injustice against the vehicle's owner, since the car is not stolen.  It was however made available to me through a sinful act, the theft of the tools.

In the case of abortion, however, as +Vigano and +Schneider point out, that evil is so grave that even the material cooperation with it would be a grave sin.  But scenario #1 makes the cooperation in the evil a formal one, not just a material one.

Fr. Copenhagen mentions it also.  In the case where the DNA is in the ναccιnє, there is an ongoing current sin which cannot be excused by way of remote or material, the abuse and theft of the bodily remains of the child.

Here's another metaphor:

1) I buy a car that was stolen from someone else.
VS.
2) I buy a car that someone repaired with stolen tools.

In case #2, my mere possession of the car is not an ongoing sin of injustice against the vehicle's owner, since the car is not stolen.  It was however made available to me through a sinful act, the theft of the tools.

In the case of abortion, however, as +Vigano and +Schneider point out, that evil is so grave that even the material cooperation with it would be a grave sin.  But scenario #1 makes the cooperation in the evil a formal one, not just a material one.

So now that the core principle is laid out, let's amend #2 to make it more like our example:

2) I buy a car that someone repaired with tools that he killed someone to obtain.

So, here as we add more aggravating circuмstances, making the crime in which we're participating materially more grave, so much more grave must be the justifying reason for participating.

Why obscure the matter, in order to make a more compelling argument for yourself?
We aren't discussing car thefts, but abortions:
ναccιnє #1: We obtained cells to test this ναccιnє by murder.

ναccιnє #2: We put murdered baby cells into the ναccιnє.

The use of the cells differs, but complicity in murder is integral to both (i.e., "Yes, I know you murdered a baby to test this ναccιnє,  Please give it to me" versus "Yes, I know there are murdered baby parts in this ναccιnє.  Please give it to me").

The moral complicity seems the same to me.
If you want to make the car theft argument, it is only an additional, supplemental, and secondary argument:
The real evil here is not unjust possession, but murder.

That's me^^^^