Latex font error - does not print helveticaboldoblique

After I compile my PNAS journal document, a part of the references should be in helvetica-boldoblique style. However, it is printed simple bold (helvetica-bold). When I change the font settings in the style and class file from boldoblique to oblique, it text will be italic but not bold anymore.

I have tried this solution, but it is not working: Latex font error ... I can't find 'hv'

Files available at: http://www.pnas.org/site/authors/LaTex.xhtml

• This is a very late welcome, but welcome to TeX.SX! You can have a look at our starter guide to familiarize yourself further with our format. It's unlike us to miss a first post like this. Could you add a minimal working example (MWE) that illustrates your problem? It will be much easier for us to reproduce your situation and find out what the issue is when we see compilable code, starting with \documentclass{...} and ending with \end{document}. – Sean Allred Jan 16 '14 at 18:33
• How do you load the fonts? – Mico Jan 16 '14 at 19:44

Without a MWE it's extremely hard to tell, but this is classic (and expected) behavior when you use the deprecated styling commands \bf and \it.

LaTeX uses two classes of commands for the job.

• One class behaves similar to \bf and \it, but they are called \bfseries and \itshape. These should be enclosed in braces to limit the scope of their effect:

{\bfseries Bold   text}
{\itshape  Italic text}
{\bfseries\itshape Bold {\em and} italic text!}

• The other class takes arguments for the scope, and can perform some intelligent corrections to typography as a result.

\textbf{Bold   text}
\textit{Italic text}
\textbf{\textit{Bold \emph{and} italic text!}


See "Correct" way to bold/italicize text? for an in-depth discussion of these commands and the differences between them.